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crontab [2013/01/27 21:29] (current)
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 +====== crontab ======
 +
 +
 +===== About crontab =====
 +              <​p>​List of files that you want to
 +            run on a regular schedule.</​p>​
 +
 +===== Syntax =====
 +              <​p>//​crontab [-e] [-l] [-r]
 +              [filename]//</​p>​
 +              <table border''"​0"​ cellpadding''"​0"​ cellspacing''"​0"​ width''"​100%">​
 +                <​tbody><​tr>​
 +                  <td valign''"​top"​ width''"​120">​-e</​td>​
 +                  <td valign''"​top">​edit a copy of the current user'​s ​ crontab ​  ​file, ​              ​or ​ creates an empty file to edit if crontab ​ does               not exist. When editing is complete, the  file  is               ​installed ​ as the user's crontab ​ file. If a user-               name is given, the specified user's crontab ​  file
 +                    is  edited, rather than the current user's crontab ​              file; this may only be done by a  super-user. ​ The
 +                    environment ​ variable EDITOR determines which editor is invoked with the  -e  option. ​ The  default ​              ​editor is
 +                    <a href''"​ued.htm">​ed</​a>​. Note that all crontab jobs should ​              be submitted using crontab ; you  should ​ not  add               ​jobs ​ by  just  editing ​ the crontab ​ file because ​              ​cron ​ will not be aware of changes made this way.</​td>​
 +
 +                </tr>
 +                <tr>
 +                  <td valign''"​top"​ width''"​120">​-l</​td>​
 +                  <td valign''"​top">​list the crontab ​  ​file ​ for  the  invoking ​ user.               Only a super-user can specify a username following ​              the -r or -l options to remove or list the crontab
 +                    file of the specified user.</​td>​
 +                </tr>
 +                <tr>
 +                  <td valign''"​top"​ width''"​120">​-r</​td>​
 +
 +                  <td valign''"​top">​remove ​ a  user'​s ​  ​crontab ​  ​from ​  ​the ​  ​crontab</​td>​
 +                </tr>
 +                <tr>
 +                  <td valign''"​top"​ width''"​120">​filename</​td>​
 +                  <td valign''"​top">​The filename that contains the commands to run.</​td>​
 +                </tr>
 +              </​tbody></​table>​
 +
 +              <​blockquote>​
 +            <​p>​**Lines that can be in the crontab file.**
 +            </​p><​p>​minute (0-59),
 +
 +         hour (0-23),
 +
 +         day of the month (1-31),
 +
 +         month of the year (1-12),
 +
 +
 +         day of the week (0-6 with 0''​Sunday).
 +              </​p></​blockquote>​
 +===== Examples =====
 +              <​p>​**crontab
 +              -e ''​ **edits the crontab file to be used.
 +            </​p><​p>​0 12 14 2** mailx john%Happy Birthday!%Time for lunch.
 +            </​p><​p>​Below is a table that represents what each of the
 +            above fields are for.
 +              </​p><​table border''"​0"​ cellpadding''"​0"​ cellspacing''"​0">​
 +                <​tbody><​tr>​
 +                  <td valign''"​top">​min</​td>​
 +
 +                  <td valign''"​top">​hour</​td>​
 +                  <td valign''"​top">​dayofmonth</​td>​
 +                  <td valign''"​top">​monthofyear</​td>​
 +                  <td valign''"​top">​dayofweek</​td>​
 +                  <td valign''"​top">​command</​td>​
 +                </tr>
 +
 +                <tr>
 +                  <td valign''"​top">​0</​td>​
 +                  <td valign''"​top">​12</​td>​
 +                  <td valign''"​top">​14</​td>​
 +                  <td valign''"​top">​2</​td>​
 +                  <td valign''"​top">​**</​td>​
 +
 +                  <td valign''"​top">​ mailx john%Happy Birthday!%Time for lunch.</​td>​
 +                </tr>
 +              </​tbody></​table>​
 +            <​p>&​nbsp;​
 +              </​p><​table border''"​0"​ cellpadding''"​0"​ cellspacing''"​0">​
 +                <​tbody><​tr>​
 +                  <td align''"​center">​**Options**</​td>​
 +
 +                  <​td>​**Explanation**</​td>​
 +                </tr>
 +                <tr>
 +                  <td align''"​center">​**</​td>​
 +                  <​td>​Is treated as a <a href''"​../​jargon/​w/​wildcard.htm">​ wild
 +                    card</​a>​. Meaning any possible value.
 +                  </td>
 +                </tr>
 +
 +                <tr>
 +                  <td align''"​center">​**/​5</​td>​
 +                  <​td>​Is treated as ever 5 minutes,
 +                    hours, days, or months. Replacing the 5 with another
 +                    numerical value will change this option.</​td>​
 +                </tr>
 +                <tr>
 +                  <td align''"​center">​2,​4,​6</​td>​
 +                  <​td>​Treated as an OR, so if
 +                    placed in the hours, this could mean at 2, 4, or 6
 +                    o-clock.</​td>​
 +
 +                </tr>
 +                <tr>
 +                  <td align''"​center">​9-17</​td>​
 +                  <​td>​Treats for any value between
 +                    9 and 17. So if placed in day of month this would be days 9
 +                    through 17. Or if put in hours it would be between 9 and 5.</​td>​
 +                </tr>
 +              </​tbody></​table>​
 +              <p>If you wish to create a task to be performed once
 +              later during the day you may wish to consider using the <a href''"​uat.htm">​at
 +              command</​a>​.
 +
 +
 +
 +-- Main.FredPettis - 05 Mar 2009
  
crontab.txt ยท Last modified: 2013/01/27 21:29 (external edit)