Merge pull request #463 from nkorth/master

Added crontab cheat sheet goodie

lib/DDG/Goodie/CrontabCheatSheet.pm

@@ -0,0 +1,62 @@
+package DDG::Goodie::CrontabCheatSheet;
+# ABSTRACT: Some examples of crontab syntax
+
+# Adapted from VimCheatSheet.pm
+
+use DDG::Goodie;
+
+zci answer_type => "cron_cheat";
+
+name "CrontabCheatSheet";
+description "Crontab cheat sheet";
+code_url "https://github.com/duckduckgo/zeroclickinfo-goodies/blob/master/lib/DDG/Goodie/CrontabCheatSheet.pm";
+category "cheat_sheets";
+topics "computing", "geek", "programming", "sysadmin";
+
+primary_example_queries 'crontab help', 'crontab cheat sheet', 'crontab example';
+
+triggers startend => (
+    'cron cheat sheet', 
+    'cron cheatsheet', 
+    'cron guide',
+    'cron help',
+    'cron quick reference',
+    'cron reference',
+    'cron example',
+    'cron examples',
+    'crontab cheat sheet', 
+    'crontab cheatsheet', 
+    'crontab guide',
+    'crontab help',
+    'crontab quick reference',
+    'crontab reference',
+    'crontab example',
+    'crontab examples'
+);
+
+attribution github  => ["nkorth", "Nathan Korth"];
+
+handle remainder => sub {
+    return 
+        heading => 'Cron Cheat Sheet',
+        html    => html_cheat_sheet(),
+        answer  => text_cheat_sheet(),
+};
+
+my $HTML;
+
+sub html_cheat_sheet {
+    $HTML //= share("crontab_cheat_sheet.html")
+        ->slurp(iomode => '<:encoding(UTF-8)');
+    return $HTML;
+}
+
+my $TEXT;
+
+sub text_cheat_sheet {
+    $TEXT //= share("crontab_cheat_sheet.txt")
+        ->slurp(iomode => '<:encoding(UTF-8)');
+    return $TEXT;
+}
+
+1;

share/goodie/crontab_cheat_sheet/crontab_cheat_sheet.html

@@ -0,0 +1,75 @@
+<style type="text/css">
+    .zci--answer .crontab-container {
+        max-height: 23.3ex;
+        overflow-y: auto;
+    }
+    .zci--answer .crontab-container .crontab-column {
+        width: 48%;
+        display: inline-block;
+        vertical-align:top;
+    }
+    .zci--answer .crontab-container .crontab-column:first-child {
+        margin-right: 3%;
+    }
+    .zci--answer .crontab-container p,
+    .zci--answer .crontab-container .crontab-column {
+        padding-top: 0;
+        padding-bottom: 2ex;
+    }
+    .zci--answer .crontab-container table {
+        width: 100%;
+    }
+    .zci--answer .crontab-container th {
+        font-weight: bold;
+    }
+    .zci--answer .crontab-container td {
+        vertical-align: top;
+    }
+    .zci--answer .crontab-container dd {
+        margin-bottom: 1ex;
+    }
+    @media(max-width: 704px) {
+        .zci--answer .crontab-container .crontab-column {
+            width: 100%;
+            margin-right: 0;
+            display: block;
+        }
+    }
+</style>
+<div class="crontab-container">
+    <div class="crontab-column">
+        <p>Commands are executed by cron when the minute, hour, and month 
+        fields match the current time, and at least one of the two day fields 
+        (day of month, or day of week) match the current time. A field may be
+        an asterisk (<code>*</code>), which will always match.</p>
+        <table>
+            <tr><th>Field</th><th>Allowed values</th>
+            <tr><td>minute</td><td>0-59</td></tr>
+            <tr><td>hour</td><td>0-23</td></tr>
+            <tr><td>day of month</td><td>1-31</td></tr>
+            <tr><td>month</td><td>1-12 or first three letters</td></tr>
+            <tr><td>day of week</td><td>0-7 or first three letters<br>(0 or 7 is Sunday)</td></tr>
+        </table>
+    </div>
+    <div class="crontab-column">
+        <b>Examples</b>
+        <dl>
+            <dt>Run every Tuesday at 2:30</dt>
+            <dd><code>30 2 * * tue  /path/to/command</code></dd>
+            <dt>Run every 10 minutes</dt>
+            <dd><code>*/10 * * * * /path/to/command</code></dd>
+            <dt>Run every 2 hours, on the half hour</dt>
+            <dd><code>30 */2 * * * /path/to/command</code></dd>
+            <dt>Run every 2 hours, on the half hour, but only on weekdays</dt>
+            <dd><code>30 */2 * * 1-5 /path/to/command</code></dd>
+            <dt>Run at 12:05, 13:05, ..., and 18:05</dt>
+            <dd><code>5 12-18 * * * /path/to/command</code></dd>
+            <dt>Run at 12:05, 14:05, 16:05, and 18:05</dt>
+            <dd><code>5 12-18/2 * * * /path/to/command</code></dd>
+            <dt>Run on the first day of every month, at midnight</dt>
+            <dd><code>0 0 1 * * /path/to/command</code></dd>
+            <dt>Run on the first day of every third month, at midnight</dt>
+            <dd><code>0 0 1 */3 * /path/to/command</code></dd>
+        </dl>
+    </div>
+</div>

share/goodie/crontab_cheat_sheet/crontab_cheat_sheet.txt

@@ -0,0 +1,37 @@
+# Commands are executed by cron when the minute, hour, and month of year 
+# fields match the current time, and at least one of the two day fields 
+# (day of month, or day of week) match the current time. A field may be
+# an asterisk (*), which will always match.
+# 
+# Fields in order:
+#   minute          (0-59)
+#   hour            (0-23)
+#   day of month    (1-31)
+#   month           (1-12 or first three letters)
+#   day of week     (0-7 or first three letters; 0 or 7 is Sunday)
+
+# Run every Tuesday at 2:30am
+30 2 * * tue    /path/to/command
+# or
+30 2 * * 2      /path/to/command
+
+# Run every 10 minutes
+*/10 * * * *    /path/to/command
+
+# Run every 2 hours, on the half-hour
+30 */2 * * *    /path/to/command
+
+# Run every 2 hours on the half hour, but only on weekdays
+30 */2 * * 1-5  /path/to/command
+
+# Run at 12:05, 13:05, ..., and 18:05
+5 12-18 * * *   /path/to/command
+
+# Run at 12:05, 14:05, 16:05, and 18:05
+5 12-18/2 * * * /path/to/command
+
+# Run on the first day of every month, at 12:00am
+0 0 1 * *       /path/to/command
+
+# Run on the first day of every third month, at 12:00am
+0 0 1 */3 *     /path/to/command