/usr/share/doc/zsh-common/html/Calendar-Function-System.html is in zsh-doc 5.3.1-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 6.3, http://www.gnu.org/software/texinfo/ -->
<head>
<title>zsh: 23 Calendar Function System</title>
<meta name="description" content="zsh: 23 Calendar Function System">
<meta name="keywords" content="zsh: 23 Calendar Function System">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="texi2any">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smalllisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>
</head>
<body lang="en">
<a name="Calendar-Function-System"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="Zsh-Modules.html#Zsh-Modules" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="Zsh-Modules.html#The-zsh_002fzutil-Module" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Description-6" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Calendar-Function-System-1"></a>
<h1 class="chapter">23 Calendar Function System</h1>
<p><a name="index-calendar-function-system"></a>
<a name="index-zsh_002fdatetime_002c-function-system-based-on"></a>
</p>
<hr>
<a name="Description-6"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-and-Date-Formats" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h2 class="section">23.1 Description</h2>
<p>The shell is supplied with a series of functions to replace and enhance the
traditional Unix <tt>calendar</tt> programme, which warns the user of imminent
or future events, details of which are stored in a text file (typically
<tt>calendar</tt> in the user’s home directory). The version provided here
includes a mechanism for alerting the user when an event is due.
</p>
<p>In addition functions <tt>age</tt>, <tt>before</tt> and <tt>after</tt> are provided
that can be used in a glob qualifier; they allow files to be selected
based on their modification times.
</p>
<p>The format of the <tt>calendar</tt> file and the dates used there in and in
the <tt>age</tt> function are described first, then the functions that can
be called to examine and modify the <tt>calendar</tt> file.
</p>
<p>The functions here depend on the availability of the <tt>zsh/datetime</tt>
module which is usually installed with the shell. The library function
<tt>strptime()</tt> must be available; it is present on most recent
operating systems.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top"><a href="#Calendar-File-and-Date-Formats">23.2 File and Date Formats</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Calendar-System-User-Functions">23.3 User Functions</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Calendar-Styles">23.4 Styles</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Calendar-Utility-Functions">23.5 Utility functions</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Calendar-Bugs">23.6 Bugs</a></td><td> </td><td align="left" valign="top">
</td></tr>
</table>
<hr>
<a name="Calendar-File-and-Date-Formats"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Description-6" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-Format" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="File-and-Date-Formats"></a>
<h2 class="section">23.2 File and Date Formats</h2>
<hr>
<a name="Calendar-File-Format"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-and-Date-Formats" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-and-Date-Formats" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Date-Format" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h3 class="subsection">23.2.1 Calendar File Format</h3>
<p>The calendar file is by default <tt>~/calendar</tt>. This can be configured
by the <tt>calendar-file</tt> style, see
<a href="#Calendar-Styles">Styles</a>. The basic format consists
of a series of separate lines, with no indentation, each including
a date and time specification followed by a description of the event.
</p>
<p>Various enhancements to this format are supported, based on the syntax
of Emacs calendar mode. An indented line indicates a continuation line
that continues the description of the event from the preceding line
(note the date may not be continued in this way). An initial ampersand
(<tt>&</tt>) is ignored for compatibility.
</p>
<p>An indented line on which the first non-whitespace character is <tt>#</tt>
is not displayed with the calendar entry, but is still scanned for
information. This can be used to hide information useful to the
calendar system but not to the user, such as the unique identifier
used by <tt>calendar_add</tt>.
</p>
<p>The Emacs extension that a date with no description may refer to a number
of succeeding events at different times is not supported.
</p>
<p>Unless the <tt>done-file</tt> style has been altered, any events which
have been processed are appended to the file with the same name as the
calendar file with the suffix <tt>.done</tt>, hence <tt>~/calendar.done</tt> by
default.
</p>
<p>An example is shown below.
</p>
<hr>
<a name="Date-Format"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-Format" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-and-Date-Formats" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Relative-Time-Format" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h3 class="subsection">23.2.2 Date Format</h3>
<p>The format of the date and time is designed to allow flexibility without
admitting ambiguity. (The words ‘date’ and ‘time’ are both used in the
documentation below; except where specifically noted this implies a string
that may include both a date and a time specification.) Note that there is
no localization support; month and day names must be in English and
separator characters are fixed. Matching is case insensitive, and only the
first three letters of the names are significant, although as a special
case a form beginning "month" does not match "Monday". Furthermore, time
zones are not handled; all times are assumed to be local.
</p>
<p>It is recommended that, rather than exploring the intricacies of the
system, users find a date format that is natural to them and stick to it.
This will avoid unexpected effects. Various key facts should be noted.
</p>
<ul>
<li> In particular, note the confusion between
<var>month</var><tt>/</tt><var>day</var><tt>/</tt><var>year</var> and
<var>day</var><tt>/</tt><var>month</var><tt>/</tt><var>year</var> when the month is numeric; these
formats should be avoided if at all possible. Many alternatives are
available.
</li><li> The year must be given in full to avoid confusion, and only years
from 1900 to 2099 inclusive are matched.
</li></ul>
<p>The following give some obvious examples; users finding here
a format they like and not subject to vagaries of style may skip
the full description. As dates and times are matched separately
(even though the time may be embedded in the date), any date format
may be mixed with any format for the time of day provide the
separators are clear (whitespace, colons, commas).
</p>
<div class="example">
<pre class="example">2007/04/03 13:13
2007/04/03:13:13
2007/04/03 1:13 pm
3rd April 2007, 13:13
April 3rd 2007 1:13 p.m.
Apr 3, 2007 13:13
Tue Apr 03 13:13:00 2007
13:13 2007/apr/3
</pre></div>
<p>More detailed rules follow.
</p>
<p>Times are parsed and extracted before dates. They must use colons
to separate hours and minutes, though a dot is allowed before seconds
if they are present. This limits time formats to the following:
</p>
<ul>
<li> <var>HH</var><tt>:</tt><var>MM</var>[<tt>:</tt><var>SS</var>[<tt>.</tt><var>FFFFF</var>]] [<tt>am</tt>|<tt>pm</tt>|<tt>a.m.</tt>|<tt>p.m.</tt>]
</li><li> <var>HH</var><tt>:</tt><var>MM</var><tt>.</tt><var>SS</var>[<tt>.</tt><var>FFFFF</var>] [<tt>am</tt>|<tt>pm</tt>|<tt>a.m.</tt>|<tt>p.m.</tt>]
</li></ul>
<p>Here, square brackets indicate optional elements, possibly with
alternatives. Fractions of a second are recognised but ignored. For
absolute times (the normal format require by the <tt>calendar</tt> file and the
<tt>age</tt>, <tt>before</tt> and <tt>after</tt> functions) a date is mandatory but a
time of day is not; the time returned is at the start of the date. One
variation is allowed: if <tt>a.m.</tt> or <tt>p.m.</tt> or one of their variants
is present, an hour without a minute is allowed, e.g. <tt>3 p.m.</tt>.
</p>
<p>Time zones are not handled, though if one is matched following a time
specification it will be removed to allow a surrounding date to be
parsed. This only happens if the format of the timezone is not too
unusual. The following are examples of forms that are understood:
</p>
<div class="example">
<pre class="example">+0100
GMT
GMT-7
CET+1CDT
</pre></div>
<p>Any part of the timezone that is not numeric must have exactly three
capital letters in the name.
</p>
<p>Dates suffer from the ambiguity between <var>DD</var><tt>/</tt><var>MM</var><tt>/</tt><var>YYYY</var>
and <var>MM</var><tt>/</tt><var>DD</var><tt>/</tt><var>YYYY</var>. It is recommended this form is
avoided with purely numeric dates, but use of ordinals,
eg. <tt>3rd/04/2007</tt>, will resolve the ambiguity as the ordinal is always
parsed as the day of the month. Years must be four digits (and the first
two must be <tt>19</tt> or <tt>20</tt>); <tt>03/04/08</tt> is not recognised. Other
numbers may have leading zeroes, but they are not required. The following
are handled:
</p>
<ul>
<li> <var>YYYY</var><tt>/</tt><var>MM</var><tt>/</tt><var>DD</var>
</li><li> <var>YYYY</var><tt>-</tt><var>MM</var><tt>-</tt><var>DD</var>
</li><li> <var>YYYY</var><tt>/</tt><var>MNM</var><tt>/</tt><var>DD</var>
</li><li> <var>YYYY</var><tt>-</tt><var>MNM</var><tt>-</tt><var>DD</var>
</li><li> <var>DD</var>[<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>] <var>MNM</var>[<tt>,</tt>] [ <var>YYYY</var> ]
</li><li> <var>MNM</var> <var>DD</var>[<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>][<tt>,</tt>] [ <var>YYYY</var> ]
</li><li> <var>DD</var>[<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>]<tt>/</tt><var>MM</var>[<tt>,</tt>] <var>YYYY</var>
</li><li> <var>DD</var>[<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>]<tt>/</tt><var>MM</var><tt>/</tt><var>YYYY</var>
</li><li> <var>MM</var><tt>/</tt><var>DD</var>[<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>][<tt>,</tt>] <var>YYYY</var>
</li><li> <var>MM</var><tt>/</tt><var>DD</var>[<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>]<tt>/</tt><var>YYYY</var>
</li></ul>
<p>Here, <var>MNM</var> is at least the first three letters of a month name,
matched case-insensitively. The remainder of the month name may appear but
its contents are irrelevant, so janissary, febrile, martial, apricot,
maybe, junta, etc. are happily handled.
</p>
<p>Where the year is shown as optional, the current year is assumed. There
are only two such cases, the form <tt>Jun 20</tt> or <tt>14 September</tt> (the only
two commonly occurring forms, apart from a "the" in some forms of English,
which isn’t currently supported). Such dates will of course become
ambiguous in the future, so should ideally be avoided.
</p>
<p>Times may follow dates with a colon, e.g. <tt>1965/07/12:09:45</tt>; this is in
order to provide a format with no whitespace. A comma and whitespace are
allowed, e.g. <tt>1965/07/12, 09:45</tt>. Currently the order of these
separators is not checked, so illogical formats such as <tt>1965/07/12, :
,09:45</tt> will also be matched. For simplicity such variations are not shown
in the list above. Otherwise, a time is only recognised as being
associated with a date if there is only whitespace in between, or if the
time was embedded in the date.
</p>
<p>Days of the week are not normally scanned, but will be ignored if they
occur at the start of the date pattern only. However, in contexts where it
is useful to specify dates relative to today, days of the week with no
other date specification may be given. The day is assumed to be either
today or within the past week. Likewise, the words <tt>yesterday</tt>,
<tt>today</tt> and <tt>tomorrow</tt> are handled. All matches are case-insensitive.
Hence if today is Monday, then <tt>Sunday</tt> is equivalent to <tt>yesterday</tt>,
<tt>Monday</tt> is equivalent to <tt>today</tt>, but <tt>Tuesday</tt> gives a date six
days ago. This is not generally useful within the calendar file.
Dates in this format may be combined with a time specification; for
example <tt>Tomorrow, 8 p.m.</tt>.
</p>
<p>For example, the standard date format:
</p>
<div class="example">
<pre class="example">Fri Aug 18 17:00:48 BST 2006
</pre></div>
<p>is handled by matching <var>HH</var><tt>:</tt><var>MM</var><tt>:</tt><var>SS</var> and removing it
together with the matched (but unused) time zone. This leaves the following:
</p>
<div class="example">
<pre class="example">Fri Aug 18 2006
</pre></div>
<p><tt>Fri</tt> is ignored and the rest is matched according to the standard rules.
</p>
<hr>
<a name="Relative-Time-Format"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Date-Format" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-and-Date-Formats" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Example-3" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h3 class="subsection">23.2.3 Relative Time Format</h3>
<p>In certain places relative times are handled. Here, a date is not allowed;
instead a combination of various supported periods are allowed, together
with an optional time. The periods must be in order from most to
least significant.
</p>
<p>In some cases, a more accurate calculation is possible when there is an
anchor date: offsets of months or years pick the correct day, rather than
being rounded, and it is possible to pick a particular day in a month as
‘(1st Friday)’, etc., as described in more detail below.
</p>
<p>Anchors are available in the following cases. If one or two times are
passed to the function <tt>calendar</tt>, the start time acts an anchor for the
end time when the end time is relative (even if the start time is
implicit). When examining calendar files, the scheduled event being
examined anchors the warning time when it is given explicitly by means of
the <tt>WARN</tt> keyword; likewise, the scheduled event anchors a repetition
period when given by the <tt>RPT</tt> keyword, so that specifications such as
<tt>RPT 2 months, 3rd Thursday</tt> are handled properly. Finally, the <tt>-R</tt>
argument to <tt>calendar_scandate</tt> directly provides an anchor for relative
calculations.
</p>
<p>The periods handled, with possible abbreviations are:
</p>
<dl compact="compact">
<dt>Years</dt>
<dd><p><tt>years</tt>, <tt>yrs</tt>, <tt>ys</tt>, <tt>year</tt>, <tt>yr</tt>, <tt>y</tt>, <tt>yearly</tt>.
A year is 365.25 days unless there is an anchor.
</p>
</dd>
<dt>Months</dt>
<dd><p><tt>months</tt>, <tt>mons</tt>, <tt>mnths</tt>, <tt>mths</tt>, <tt>month</tt>, <tt>mon</tt>,
<tt>mnth</tt>, <tt>mth</tt>, <tt>monthly</tt>. Note that <tt>m</tt>, <tt>ms</tt>, <tt>mn</tt>, <tt>mns</tt>
are ambiguous and are <em>not</em> handled. A month is a period
of 30 days rather than a calendar month unless there is an anchor.
</p>
</dd>
<dt>Weeks</dt>
<dd><p><tt>weeks</tt>, <tt>wks</tt>, <tt>ws</tt>, <tt>week</tt>, <tt>wk</tt>, <tt>w</tt>, <tt>weekly</tt>
</p>
</dd>
<dt>Days</dt>
<dd><p><tt>days</tt>, <tt>dys</tt>, <tt>ds</tt>, <tt>day</tt>, <tt>dy</tt>, <tt>d</tt>, <tt>daily</tt>
</p>
</dd>
<dt>Hours</dt>
<dd><p><tt>hours</tt>, <tt>hrs</tt>, <tt>hs</tt>, <tt>hour</tt>, <tt>hr</tt>, <tt>h</tt>, <tt>hourly</tt>
</p>
</dd>
<dt>Minutes</dt>
<dd><p><tt>minutes</tt>, <tt>mins</tt>, <tt>minute</tt>, <tt>min</tt>, but <em>not</em> <tt>m</tt>,
<tt>ms</tt>, <tt>mn</tt> or <tt>mns</tt>
</p>
</dd>
<dt>Seconds</dt>
<dd><p><tt>seconds</tt>, <tt>secs</tt>, <tt>ss</tt>, <tt>second</tt>, <tt>sec</tt>, <tt>s</tt>
</p>
</dd>
</dl>
<p>Spaces between the numbers are optional, but are required between items,
although a comma may be used (with or without spaces).
</p>
<p>The forms <tt>yearly</tt> to <tt>hourly</tt> allow the number to be omitted; it is
assumed to be 1. For example, <tt>1 d</tt> and <tt>daily</tt> are equivalent. Note
that using those forms with plurals is confusing; <tt>2 yearly</tt> is the same
as <tt>2 years</tt>, <em>not</em> twice yearly, so it is recommended they only
be used without numbers.
</p>
<p>When an anchor time is present, there is an extension to handle regular
events in the form of the <var>n</var>th <var>some</var>day of the month. Such a
specification must occur immediately after any year and month
specification, but before any time of day, and must be in the form
<var>n</var>(<tt>th</tt>|<tt>st</tt>|<tt>rd</tt>) <var>day</var>, for example <tt>1st Tuesday</tt> or
<tt>3rd Monday</tt>. As in other places, days are matched case insensitively,
must be in English, and only the first three letters are significant except
that a form beginning ‘month’ does not match ‘Monday’. No attempt is made
to sanitize the resulting date; attempts to squeeze too many occurrences
into a month will push the day into the next month (but in the obvious
fashion, retaining the correct day of the week).
</p>
<p>Here are some examples:
</p>
<div class="example">
<pre class="example">30 years 3 months 4 days 3:42:41
14 days 5 hours
Monthly, 3rd Thursday
4d,10hr
</pre></div>
<hr>
<a name="Example-3"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Relative-Time-Format" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-File-and-Date-Formats" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-System-User-Functions" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h3 class="subsection">23.2.4 Example</h3>
<p>Here is an example calendar file. It uses a consistent date format,
as recommended above.
</p>
<div class="example">
<pre class="example">Feb 1, 2006 14:30 Pointless bureaucratic meeting
Mar 27, 2006 11:00 Mutual recrimination and finger pointing
Bring water pistol and waterproofs
Mar 31, 2006 14:00 Very serious managerial pontification
# UID 12C7878A9A50
Apr 10, 2006 13:30 Even more pointless blame assignment exercise WARN 30 mins
May 18, 2006 16:00 Regular moaning session RPT monthly, 3rd Thursday
</pre></div>
<p>The second entry has a continuation line. The third entry has a
continuation line that will not be shown when the entry is displayed, but
the unique identifier will be used by the <tt>calendar_add</tt> function when
updating the event. The fourth entry will produce a warning 30 minutes
before the event (to allow you to equip yourself appropriately). The fifth
entry repeats after a month on the 3rd Thursday, i.e. June 15, 2006, at the
same time.
</p>
<hr>
<a name="Calendar-System-User-Functions"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Example-3" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-system-functions" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="User-Functions"></a>
<h2 class="section">23.3 User Functions</h2>
<p>This section describes functions that are designed to be called
directly by the user. The first part describes those functions
associated with the user’s calendar; the second part describes
the use in glob qualifiers.
</p>
<hr>
<a name="Calendar-system-functions"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-System-User-Functions" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-System-User-Functions" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Glob-qualifiers" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h3 class="subsection">23.3.1 Calendar system functions</h3>
<dl compact="compact">
<dd><a name="index-calendar"></a>
</dd>
<dt><tt>calendar </tt>[ <tt>-abdDsv</tt> ] [ <tt>-C</tt> <var>calfile</var> ] [ <tt>-n</tt> <var>num</var> ] [ <tt>-S</tt> <var>showprog</var> ]</dt>
<dt><tt> </tt>[ [ <var>start</var> ] <var>end</var> ]</dt>
<dt><tt>calendar -r</tt> [ <tt>-abdDrsv</tt> ] [ <tt>-C</tt> <var>calfile</var> ] [ <tt>-n</tt> <var>num</var> ] [ <tt>-S</tt> <var>showprog</var> ]</dt>
<dt><tt> </tt>[ <var>start</var> ]</dt>
<dd><p>Show events in the calendar.
</p>
<p>With no arguments, show events from the start of today until the end of
the next working day after today. In other words, if today is Friday,
Saturday, or Sunday, show up to the end of the following Monday, otherwise
show today and tomorrow.
</p>
<p>If <var>end</var> is given, show events from the start of today up to the time
and date given, which is in the format described in the previous section.
Note that if this is a date the time is assumed to be midnight at the
start of the date, so that effectively this shows all events before
the given date.
</p>
<p><var>end</var> may start with a <tt>+</tt>, in which case the remainder of the
specification is a relative time format as described in the previous
section indicating the range of time from the start time that is to
be included.
</p>
<p>If <var>start</var> is also given, show events starting from that time and date.
The word <tt>now</tt> can be used to indicate the current time.
</p>
<p>To implement an alert when events are due, include <tt>calendar -s</tt> in your
<tt>~/.zshrc</tt> file.
</p>
<p>Options:
</p>
<dl compact="compact">
<dt><tt>-a</tt></dt>
<dd><p>Show all items in the calendar, regardless of the <tt>start</tt> and
<tt>end</tt>.
</p>
</dd>
<dt><tt>-b</tt></dt>
<dd><p>Brief: don’t display continuation lines (i.e. indented lines following
the line with the date/time), just the first line.
</p>
</dd>
<dt><tt>-B</tt> <var>lines</var></dt>
<dd><p>Brief: display at most the first <var>lines</var> lines of the calendar
entry. ‘<tt>-B 1</tt>’ is equivalent to ‘<tt>-b</tt>’.
</p>
</dd>
<dt><tt>-C</tt> <var>calfile</var></dt>
<dd><p>Explicitly specify a calendar file instead of the value of
the <tt>calendar-file</tt> style or the default <tt>~/calendar</tt>.
</p>
</dd>
<dt><tt>-d</tt></dt>
<dd><p>Move any events that have passed from the calendar file to the
"done" file, as given by the <tt>done-file</tt> style or the default
which is the calendar file with <tt>.done</tt> appended. This option
is implied by the <tt>-s</tt> option.
</p>
</dd>
<dt><tt>-D</tt></dt>
<dd><p>Turns off the option <tt>-d</tt>, even if the <tt>-s</tt> option is also present.
</p>
</dd>
<dt><tt>-n</tt> <var>num</var>, <tt>-</tt><var>num</var></dt>
<dd><p>Show at least <var>num</var> events, if present in the calendar file, regardless
of the <tt>start</tt> and <tt>end</tt>.
</p>
</dd>
<dt><tt>-r</tt></dt>
<dd><p>Show all the remaining options in the calendar, ignoring the given <var>end</var>
time. The <var>start</var> time is respected; any argument given is treated
as a <var>start</var> time.
</p>
</dd>
<dt><tt>-s</tt></dt>
<dd><p>Use the shell’s <tt>sched</tt> command to schedule a timed event that
will warn the user when an event is due. Note that the <tt>sched</tt> command
only runs if the shell is at an interactive prompt; a foreground task
blocks the scheduled task from running until it is finished.
</p>
<p>The timed event usually runs the programme <tt>calendar_show</tt> to show
the event, as described in
<a href="#Calendar-Utility-Functions">Utility functions</a>.
</p>
<p>By default, a warning of the event is shown five minutes before it is due.
The warning period can be configured by the style <tt>warn-time</tt> or
for a single calendar entry by including <tt>WARN</tt> <var>reltime</var> in the first
line of the entry, where <var>reltime</var> is one of the usual relative time
formats.
</p>
<p>A repeated event may be indicated by including <tt>RPT</tt> <var>reldate</var> in the
first line of the entry. After the scheduled event has been displayed
it will be re-entered into the calendar file at a time <var>reldate</var>
after the existing event. Note that this is currently the only use
made of the repeat count, so that it is not possible to query the schedule
for a recurrence of an event in the calendar until the previous event
has passed.
</p>
<p>If <tt>RPT</tt> is used, it is also possible to specify that certain
recurrences of an event are rescheduled or cancelled. This is
done with the <tt>OCCURRENCE</tt> keyword, followed by whitespace and the
date and time of the occurrence in the regular sequence, followed by
whitespace and either the date and time of the rescheduled event or
the exact string <tt>CANCELLED</tt>. In this case the date and time must
be in exactly the "date with local time" format used by the
<tt>text/calendar</tt> MIME type (RFC 2445),
<var><YYYY><MM><DD></var><tt>T</tt><var><hh><mm><ss></var> (note the presence of the literal
character <tt>T</tt>). The first word (the regular recurrence) may be
something other than a proper date/time to indicate that the event
is additional to the normal sequence; a convention that retains
the formatting appearance is <tt>XXXXXXXXTXXXXXX</tt>.
</p>
<p>Furthermore, it is useful to record the next regular recurrence
(as then the displayed date may be for a rescheduled event so cannot
be used for calculating the regular sequence). This is specified by
<tt>RECURRENCE</tt> and a time or date in the same format. <tt>calendar_add</tt>
adds such an indication when it encounters a recurring event that does not
include one, based on the headline date/time.
</p>
<p>If <tt>calendar_add</tt> is used to update occurrences the <tt>UID</tt> keyword
described there should be present in both the existing entry and the added
occurrence in order to identify recurring event sequences.
</p>
<p>For example,
</p>
<div class="example">
<pre class="example">Thu May 6, 2010 11:00 Informal chat RPT 1 week
# RECURRENCE 20100506T110000
# OCCURRENCE 20100513T110000 20100513T120000
# OCCURRENCE 20100520T110000 CANCELLED
</pre></div>
<p>The event that occurs at 11:00 on 13th May 2010 is rescheduled an hour
later. The event that occurs a week later is cancelled. The occurrences
are given on a continuation line starting with a <tt>#</tt> character so will
not usually be displayed as part of the event. As elsewhere, no account of
time zones is taken with the times. After the next event occurs the headline
date/time will be ‘<tt>Thu May 13, 2010 12:00</tt>’ while the <tt>RECURRENCE</tt>
date/time will be ‘<tt>20100513T110000</tt>’ (note that cancelled and
moved events are not taken account of in the <tt>RECURRENCE</tt>, which
records what the next regular recurrence is, but they are accounted for in
the headline date/time).
</p>
<p>It is safe to run <tt>calendar -s</tt> to reschedule an existing event
(if the calendar file has changed, for example), and also to have it
running in multiples instances of the shell since the calendar file
is locked when in use.
</p>
<p>By default, expired events are moved to the "done" file; see the <tt>-d</tt>
option. Use <tt>-D</tt> to prevent this.
</p>
</dd>
<dt><tt>-S</tt> <var>showprog</var></dt>
<dd><p>Explicitly specify a programme to be used for showing events instead
of the value of the <tt>show-prog</tt> style or the default <tt>calendar_show</tt>.
</p>
</dd>
<dt><tt>-v</tt></dt>
<dd><p>Verbose: show more information about stages of processing. This
is useful for confirming that the function has successfully parsed
the dates in the calendar file.
</p>
</dd>
</dl>
<a name="index-calendar_005fadd"></a>
</dd>
<dt><tt>calendar_add</tt> [ <tt>-BL</tt> ] <var>event</var> ...</dt>
<dd><p>Adds a single event to the calendar in the appropriate location.
The event can contain multiple lines, as described in
<a href="#Calendar-File-and-Date-Formats">File and Date Formats</a>.
Using this function ensures that the calendar file is sorted in date
and time order. It also makes special arrangements for locking
the file while it is altered. The old calendar is left in a file
with the suffix <tt>.old</tt>.
</p>
<p>The option <tt>-B</tt> indicates that backing up the calendar file will be
handled by the caller and should not be performed by <tt>calendar_add</tt>. The
option <tt>-L</tt> indicates that <tt>calendar_add</tt> does not need to lock the
calendar file as it is already locked. These options will not usually be
needed by users.
</p>
<p>If the style <tt>reformat-date</tt> is true, the date and time of the
new entry will be rewritten into the standard date format: see
the descriptions of this style and the style <tt>date-format</tt>.
</p>
<p>The function can use a unique identifier stored with each event to ensure
that updates to existing events are treated correctly. The entry
should contain the word <tt>UID</tt>, followed by whitespace, followed by
a word consisting entirely of hexadecimal digits of arbitrary length
(all digits are significant, including leading zeroes). As the UID
is not directly useful to the user, it is convenient to hide it on
an indented continuation line starting with a <tt>#</tt>, for example:
</p>
<div class="example">
<pre class="example">Aug 31, 2007 09:30 Celebrate the end of the holidays
# UID 045B78A0
</pre></div>
<p>The second line will not be shown by the <tt>calendar</tt> function.
</p>
<p>It is possible to specify the <tt>RPT</tt> keyword followed by <tt>CANCELLED</tt>
instead of a relative time. This causes any matched event or series
of events to be cancelled (the original event does not have to be marked
as recurring in order to be cancelled by this method). A <tt>UID</tt> is
required in order to match an existing event in the calendar.
</p>
<p><tt>calendar_add</tt> will attempt to manage recurrences and occurrences of
repeating events as described for event scheduling by <tt>calendar -s</tt>
above. To reschedule or cancel a single event <tt>calendar_add</tt> should be
called with an entry that includes the correct <tt>UID</tt> but does <em>not</em>
include the <tt>RPT</tt> keyword as this is taken to mean the entry applies to a
series of repeating events and hence replaces all existing information.
Each rescheduled or cancelled occurrence must have an <tt>OCCURRENCE</tt>
keyword in the entry passed to <tt>calendar_add</tt> which will be merged into
the calendar file. Any existing reference to the occurrence is replaced.
An occurrence that does not refer to a valid existing event is added as a
one-off occurrence to the same calendar entry.
</p>
<a name="index-calendar_005fedit"></a>
</dd>
<dt><tt>calendar_edit</tt></dt>
<dd><p>This calls the user’s editor to edit the calendar file. If
there are arguments, they are taken as the editor to use (the file name
is appended to the commands); otherwise, the editor is given by the
variable <tt>VISUAL</tt>, if set, else the variable <tt>EDITOR</tt>.
</p>
<p>If the calendar scheduler was running, then after editing the file
<tt>calendar -s</tt> is called to update it.
</p>
<p>This function locks out the calendar system during the edit.
Hence it should be used to edit the calendar file if there is any
possibility of a calendar event occurring meanwhile. Note this
can lead to another shell with calendar functions enabled hanging waiting
for a lock, so it is necessary to quit the editor as soon as possible.
</p>
<a name="index-calendar_005fparse"></a>
</dd>
<dt><tt>calendar_parse</tt> <var>calendar-entry</var></dt>
<dd><p>This is the internal function that analyses the parts of a calendar
entry, which is passed as the only argument. The function returns
status 1 if the argument could not be parsed as a calendar entry
and status 2 if the wrong number of arguments were passed; it also sets the
parameter <tt>reply</tt> to an empty associative array. Otherwise,
it returns status 0 and sets elements of the associative
array <tt>reply</tt> as follows:
</p>
<dl compact="compact">
<dt><tt>time</tt></dt>
<dd><p>The time as a string of digits in the same units as
<tt>$EPOCHSECONDS</tt>
</p></dd>
<dt><tt>schedtime</tt></dt>
<dd><p>The regularly scheduled time. This may differ from
the actual event time <tt>time</tt> if this is a recurring event and the next
occurrence has been rescheduled. Then <tt>time</tt> gives the actual time
and <tt>schedtime</tt> the time of the regular recurrence before modification.
</p></dd>
<dt><tt>text1</tt></dt>
<dd><p>The text from the line not including the date and time of the
event, but including any <tt>WARN</tt> or <tt>RPT</tt> keywords and values.
</p></dd>
<dt><tt>warntime</tt></dt>
<dd><p>Any warning time given by the <tt>WARN</tt> keyword as a string
of digits containing the time at which to warn in the same units as
<tt>$EPOCHSECONDS</tt>. (Note this is an absolute time, not the relative time
passed down.) Not set no <tt>WARN</tt> keyword and value were
matched.
</p></dd>
<dt><tt>warnstr</tt></dt>
<dd><p>The raw string matched after the <tt>WARN</tt> keyword, else unset.
</p></dd>
<dt><tt>rpttime</tt></dt>
<dd><p>Any recurrence time given by the <tt>RPT</tt> keyword as a string
of digits containing the time of the recurrence in the same units
as <tt>$EPOCHSECONDS</tt>. (Note this is an absolute time.) Not set if
no <tt>RPT</tt> keyword and value were matched.
</p></dd>
<dt><tt>schedrpttime</tt></dt>
<dd><p>The next regularly scheduled occurrence of a recurring
event before modification. This may differ from <tt>rpttime</tt>, which is the
actual time of the event that may have been rescheduled from the regular
time.
</p></dd>
<dt><tt>rptstr</tt></dt>
<dd><p>The raw string matched after the <tt>RPT</tt> keyword, else unset.
</p></dd>
<dt><tt>text2</tt></dt>
<dd><p>The text from the line after removal of the date and any
keywords and values.
</p>
</dd>
</dl>
<p><a name="index-calendar_005fshowdate"></a>
</p></dd>
<dt><tt>calendar_showdate</tt> [ <tt>-r</tt> ] [ <tt>-f</tt> <var>fmt</var> ] <var>date-spec</var> ...</dt>
<dd><p>The given <var>date-spec</var> is interpreted and the corresponding date and
time printed. If the initial <var>date-spec</var> begins with a <tt>+</tt> or
<tt>-</tt> it is treated as relative to the current time; <var>date-spec</var>s after
the first are treated as relative to the date calculated so far and
a leading <tt>+</tt> is optional in that case. This allows one to
use the system as a date calculator. For example, <tt>calendar_showdate '+1
month, 1st Friday'</tt> shows the date of the first Friday of next month.
</p>
<p>With the option <tt>-r</tt> nothing is printed but the value of the date and
time in seconds since the epoch is stored in the parameter <tt>REPLY</tt>.
</p>
<p>With the option <tt>-f</tt> <var>fmt</var> the given date/time conversion format
is passed to <tt>strftime</tt>; see notes on the <tt>date-format</tt> style below.
</p>
<p>In order to avoid ambiguity with negative relative date specifications,
options must occur in separate words; in other words, <tt>-r</tt> and <tt>-f</tt>
should not be combined in the same word.
</p>
<a name="index-calendar_005fsort"></a>
</dd>
<dt><tt>calendar_sort</tt></dt>
<dd><p>Sorts the calendar file into date and time order. The old calendar is
left in a file with the suffix <tt>.old</tt>.
</p>
</dd>
</dl>
<hr>
<a name="Glob-qualifiers"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-system-functions" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-System-User-Functions" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Styles" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<h3 class="subsection">23.3.2 Glob qualifiers</h3>
<dl compact="compact">
<dt><tt>age</tt></dt>
<dd><a name="index-age"></a>
<p>The function <tt>age</tt> can be autoloaded and use separately from
the calendar system, although it uses the function <tt>calendar_scandate</tt>
for date formatting. It requires the <tt>zsh/stat</tt> builtin, but uses
only the builtin <tt>zstat</tt>.
</p>
<p><tt>age</tt> selects files having a given modification time for use
as a glob qualifier. The format of the date is the same as that
understood by the calendar system, described in
<a href="#Calendar-File-and-Date-Formats">File and Date Formats</a>.
</p>
<p>The function can take one or two arguments, which can be supplied either
directly as command or arguments, or separately as shell parameters.
</p>
<div class="example">
<pre class="example">print *(e:age 2006/10/04 2006/10/09:)
</pre></div>
<p>The example above matches all files modified between the start of those
dates. The second argument may alternatively be a relative time
introduced by a <tt>+</tt>:
</p>
<div class="example">
<pre class="example">print *(e:age 2006/10/04 +5d:)
</pre></div>
<p>The example above is equivalent to the previous example.
</p>
<p>In addition to the special use of days of the week, <tt>today</tt> and
<tt>yesterday</tt>, times with no date may be specified; these apply to today.
Obviously such uses become problematic around midnight.
</p>
<div class="example">
<pre class="example">print *(e-age 12:00 13:30-)
</pre></div>
<p>The example above shows files modified between 12:00 and 13:00 today.
</p>
<div class="example">
<pre class="example">print *(e:age 2006/10/04:)
</pre></div>
<p>The example above matches all files modified on that date. If the second
argument is omitted it is taken to be exactly 24 hours after the first
argument (even if the first argument contains a time).
</p>
<div class="example">
<pre class="example">print *(e-age 2006/10/04:10:15 2006/10/04:10:45-)
</pre></div>
<p>The example above supplies times. Note that whitespace within the time and
date specification must be quoted to ensure <tt>age</tt> receives the correct
arguments, hence the use of the additional colon to separate the date and
time.
</p>
<div class="example">
<pre class="example">AGEREF=2006/10/04:10:15
AGEREF2=2006/10/04:10:45
print *(+age)
</pre></div>
<p>This shows the same example before using another form of argument
passing. The dates and times in the parameters <tt>AGEREF</tt> and <tt>AGEREF2</tt>
stay in effect until unset, but will be overridden if any argument is
passed as an explicit argument to age. Any explicit argument
causes both parameters to be ignored.
</p>
<p>Instead of an explicit date and time, it’s possible to use the
modification time of a file as the date and time for either argument
by introducing the file name with a colon:
</p>
<div class="example">
<pre class="example">print *(e-age :file1-)
</pre></div>
<p>matches all files created on the same day (24 hours starting from
midnight) as <tt>file1</tt>.
</p>
<div class="example">
<pre class="example">print *(e-age :file1 :file2-)
</pre></div>
<p>matches all files modified no earlier than <tt>file1</tt> and
no later than <tt>file2</tt>; precision here is to the nearest second.
</p>
</dd>
<dt><tt>after</tt></dt>
<dt><tt>before</tt></dt>
<dd><a name="index-after"></a>
<a name="index-before"></a>
<p>The functions <tt>after</tt> and <tt>before</tt> are simpler versions of <tt>age</tt>
that take just one argument. The argument is parsed similarly to an
argument of <tt>age</tt>; if it is not given the variable <tt>AGEREF</tt> is
consulted. As the names of the functions suggest, a file matches if its
modification time is after or before the time and date specified. If
a time only is given the date is today.
</p>
<p>The two following examples are therefore equivalent:
</p><div class="example">
<pre class="example">print *(e-after 12:00-)
print *(e-after today:12:00-)
</pre></div>
</dd>
</dl>
<hr>
<a name="Calendar-Styles"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Glob-qualifiers" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Utility-Functions" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Styles"></a>
<h2 class="section">23.4 Styles</h2>
<p>The zsh style mechanism using the <tt>zstyle</tt> command is describe in
<a href="Zsh-Modules.html#The-zsh_002fzutil-Module">The zsh/zutil Module</a>. This is the same mechanism
used in the completion system.
</p>
<p>The styles below are all examined in the context
<tt>:datetime:</tt><var>function</var><tt>:</tt>, for example <tt>:datetime:calendar:</tt>.
</p>
<dl compact="compact">
<dd><a name="index-calendar_002dfile"></a>
</dd>
<dt><tt>calendar-file</tt></dt>
<dd><p>The location of the main calendar. The default is <tt>~/calendar</tt>.
</p>
<a name="index-date_002dformat"></a>
</dd>
<dt><tt>date-format</tt></dt>
<dd><p>A <tt>strftime</tt> format string (see man page strftime(3)) with the zsh
extensions providing various numbers with no leading zero or space
if the number is a single digit as described for the
<tt>%D{</tt><var>string</var><tt>}</tt> prompt format in
<a href="Prompt-Expansion.html#Prompt-Expansion">Prompt Expansion</a>.
</p>
<p>This is used for outputting dates in <tt>calendar</tt>, both to support
the <tt>-v</tt> option and when adding recurring events back to the calendar
file, and in <tt>calendar_showdate</tt> as the final output format.
</p>
<p>If the style is not set, the default used is similar the standard system
format as output by the <tt>date</tt> command (also known as ‘ctime format’):
‘<tt>%a %b %d %H:%M:%S %Z %Y</tt>’.
</p>
<a name="index-done_002dfile"></a>
</dd>
<dt><tt>done-file</tt></dt>
<dd><p>The location of the file to which events which have passed are appended.
The default is the calendar file location with the suffix <tt>.done</tt>.
The style may be set to an empty string in which case a "done" file
will not be maintained.
</p>
<a name="index-reformat_002ddate"></a>
</dd>
<dt><tt>reformat-date</tt></dt>
<dd><p>Boolean, used by <tt>calendar_add</tt>. If it is true, the date and time
of new entries added to the calendar will be reformatted to the format
given by the style <tt>date-format</tt> or its default. Only the date and
time of the event itself is reformatted; any subsidiary dates and times
such as those associated with repeat and warning times are left alone.
</p>
<a name="index-show_002dprog"></a>
</dd>
<dt><tt>show-prog</tt></dt>
<dd><p>The programme run by <tt>calendar</tt> for showing events. It will
be passed the start time and stop time of the events requested in seconds
since the epoch followed by the event text. Note that <tt>calendar -s</tt> uses
a start time and stop time equal to one another to indicate alerts
for specific events.
</p>
<p>The default is the function <tt>calendar_show</tt>.
</p>
<a name="index-warn_002dtime"></a>
</dd>
<dt><tt>warn-time</tt></dt>
<dd><p>The time before an event at which a warning will be displayed, if the
first line of the event does not include the text <tt>EVENT</tt> <var>reltime</var>.
The default is 5 minutes.
</p>
</dd>
</dl>
<hr>
<a name="Calendar-Utility-Functions"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Styles" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Bugs" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Utility-functions"></a>
<h2 class="section">23.5 Utility functions</h2>
<dl compact="compact">
<dd><a name="index-calendar_005flockfiles"></a>
</dd>
<dt><tt>calendar_lockfiles</tt></dt>
<dd><p>Attempt to lock the files given in the argument. To prevent
problems with network file locking this is done in an ad hoc fashion
by attempting to create a symbolic link to the file with the name
<var>file</var><tt>.lockfile</tt>. No other system level functions are used
for locking, i.e. the file can be accessed and modified by any
utility that does not use this mechanism. In particular, the user is not
prevented from editing the calendar file at the same time unless
<tt>calendar_edit</tt> is used.
</p>
<p>Three attempts are made to lock the file before giving up. If the module
<tt>zsh/zselect</tt> is available, the times of the attempts are jittered so that
multiple instances of the calling function are unlikely to retry at the
same time.
</p>
<p>The files locked are appended to the array <tt>lockfiles</tt>, which should
be local to the caller.
</p>
<p>If all files were successfully locked, status zero is returned, else status one.
</p>
<p>This function may be used as a general file locking function, although
this will only work if only this mechanism is used to lock files.
</p>
<a name="index-calendar_005fread"></a>
</dd>
<dt><tt>calendar_read</tt></dt>
<dd><p>This is a backend used by various other functions to parse the
calendar file, which is passed as the only argument. The array
<tt>calendar_entries</tt> is set to the list of events in the file; no
pruning is done except that ampersands are removed from the start of
the line. Each entry may contain multiple lines.
</p>
<a name="index-calendar_005fscandate"></a>
</dd>
<dt><tt>calendar_scandate</tt></dt>
<dd><p>This is a generic function to parse dates and times that may be
used separately from the calendar system. The argument is a date
or time specification as described in
<a href="#Calendar-File-and-Date-Formats">File and Date Formats</a>. The parameter <tt>REPLY</tt>
is set to the number of seconds since the epoch corresponding to that date
or time. By default, the date and time may occur anywhere within the given
argument.
</p>
<p>Returns status zero if the date and time were successfully parsed,
else one.
</p>
<p>Options:
</p><dl compact="compact">
<dt><tt>-a</tt></dt>
<dd><p>The date and time are anchored to the start of the argument; they
will not be matched if there is preceding text.
</p>
</dd>
<dt><tt>-A</tt></dt>
<dd><p>The date and time are anchored to both the start and end of the argument;
they will not be matched if the is any other text in the argument.
</p>
</dd>
<dt><tt>-d</tt></dt>
<dd><p>Enable additional debugging output.
</p>
</dd>
<dt><tt>-m</tt></dt>
<dd><p>Minus. When <tt>-R</tt> <var>anchor_time</var> is also given the relative time is
calculated backwards from <var>anchor_time</var>.
</p>
</dd>
<dt><tt>-r</tt></dt>
<dd><p>The argument passed is to be parsed as a relative time.
</p>
</dd>
<dt><tt>-R</tt> <var>anchor_time</var></dt>
<dd><p>The argument passed is to be parsed as a relative time. The time is
relative to <var>anchor_time</var>, a time in seconds since the epoch,
and the returned value is the absolute time corresponding to advancing
<var>anchor_time</var> by the relative time given.
This allows lengths of months to be correctly taken into account. If
the final day does not exist in the given month, the last day of the
final month is given. For example, if the anchor time is during 31st
January 2007 and the relative time is 1 month, the final time is the
same time of day during 28th February 2007.
</p>
</dd>
<dt><tt>-s</tt></dt>
<dd><p>In addition to setting <tt>REPLY</tt>, set <tt>REPLY2</tt> to the remainder of
the argument after the date and time have been stripped. This is
empty if the option <tt>-A</tt> was given.
</p>
</dd>
<dt><tt>-t</tt></dt>
<dd><p>Allow a time with no date specification. The date is assumed to be
today. The behaviour is unspecified if the iron tongue of midnight
is tolling twelve.
</p>
</dd>
</dl>
<a name="index-calendar_005fshow"></a>
</dd>
<dt><tt>calendar_show</tt></dt>
<dd><p>The function used by default to display events. It accepts a start time
and end time for events, both in epoch seconds, and an event description.
</p>
<p>The event is always printed to standard output. If the command line editor
is active (which will usually be the case) the command line will be
redisplayed after the output.
</p>
<p>If the parameter <tt>DISPLAY</tt> is set and the start and end times are
the same (indicating a scheduled event), the function uses the
command <tt>xmessage</tt> to display a window with the event details.
</p>
</dd>
</dl>
<hr>
<a name="Calendar-Bugs"></a>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Utility-Functions" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Bugs"></a>
<h2 class="section">23.6 Bugs</h2>
<p>As the system is based entirely on shell functions (with a little support
from the <tt>zsh/datetime</tt> module) the mechanisms used are not as robust as
those provided by a dedicated calendar utility. Consequently the user
should not rely on the shell for vital alerts.
</p>
<p>There is no <tt>calendar_delete</tt> function.
</p>
<p>There is no localization support for dates and times, nor any support
for the use of time zones.
</p>
<p>Relative periods of months and years do not take into account the variable
number of days.
</p>
<p>The <tt>calendar_show</tt> function is currently hardwired to use <tt>xmessage</tt>
for displaying alerts on X Window System displays. This should be
configurable and ideally integrate better with the desktop.
</p>
<p><tt>calendar_lockfiles</tt> hangs the shell while waiting for a lock on a file.
If called from a scheduled task, it should instead reschedule the event
that caused it.
</p><hr>
<table class="header" cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Calendar-Function-System" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="TCP-Function-System.html#TCP-Function-System" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="index.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="zsh_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Concept-Index.html#Concept-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="zsh_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<p><font size="-1">
This document was generated on <em>April 11, 2017</em> using <a href="http://www.gnu.org/software/texinfo/"><em>texi2any</em></a>.
</font></p>
<font size="-1">Zsh version 5.3.1, released on December 21, 2016.</font>
</body>
</html>
|