Alexandre Detiste
parent
015aa15825
commit
1e0f599b0c
135
man/crontab.5
135
man/crontab.5
@ -93,41 +93,43 @@ LOGNAME is the user that the job is running from, and may not be changed.
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(Another note: the LOGNAME variable is sometimes called USER on BSD systems...
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on these systems, USER will be set also.)
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.PP
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In addition to LOGNAME, HOME, and SHELL,
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.IR cron (8)
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will look at MAILTO if it has any reason to send mail as a result of running
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commands in ``this'' crontab. If MAILTO is defined (and non-empty), mail is
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sent to the user so named. MAILTO may also be used to direct mail to multiple
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recipients by separating recipient users with a comma. If MAILTO is defined
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but empty (MAILTO=""), no mail will be sent. Otherwise mail is sent to the
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owner of the crontab.
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.PP
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./On the Debian GNU/Linux system, cron supports the
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./.B pam_env
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./module, and loads the environment specified by
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./.IR /etc/environment
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./and
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./.IR /etc/security/pam_env.conf .
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./It also reads locale information from
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./.IR /etc/default/locale .
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./However, the PAM settings do
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./.B NOT
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./override the settings described above nor any settings in the
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./.I crontab
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./file itself. Note in particular that if you want a PATH other than
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./"/usr/bin:/bin", you will need to set it in the crontab file.
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./.PP
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By default, cron will send mail using the mail "Content-Type:" header of
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"text/plain" with the "charset=" parameter set to the charmap / codeset of the
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locale in which
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.IR crond (8)
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is started up - ie. either the default system locale, if no LC_* environment
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variables are set, or the locale specified by the LC_* environment variables
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( see
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.IR locale (7) ).
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You can use different character encodings for mailed cron job output by
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setting the CONTENT_TYPE and CONTENT_TRANSFER_ENCODING variables in crontabs,
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to the correct values of the mail headers of those names.
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systemd-crontab-generator doesn't set the MAILTO variable nor send
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any mails like vixie-cron. The output of jobs is written in the journal.
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.\"In addition to LOGNAME, HOME, and SHELL,
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.\".IR cron (8)
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.\"will look at MAILTO if it has any reason to send mail as a result of running
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.\"commands in ``this'' crontab. If MAILTO is defined (and non-empty), mail is
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.\"sent to the user so named. MAILTO may also be used to direct mail to multiple
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.\"recipients by separating recipient users with a comma. If MAILTO is defined
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.\"but empty (MAILTO=""), no mail will be sent. Otherwise mail is sent to the
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.\"owner of the crontab.
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.\".PP
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.\"On the Debian GNU/Linux system, cron supports the
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.\".B pam_env
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.\"module, and loads the environment specified by
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.\".IR /etc/environment
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.\"and
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.\".IR /etc/security/pam_env.conf .
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.\"It also reads locale information from
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.\".IR /etc/default/locale .
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.\"However, the PAM settings do
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.\".B NOT
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.\"override the settings described above nor any settings in the
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.\".I crontab
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.\"file itself. Note in particular that if you want a PATH other than
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.\" "/usr/bin:/bin", you will need to set it in the crontab file.
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.\".PP
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.\"By default, cron will send mail using the mail "Content-Type:" header of
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.\" "text/plain" with the "charset=" parameter set to the charmap / codeset of the
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.\"locale in which
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.\".IR crond (8)
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.\"is started up - ie. either the default system locale, if no LC_* environment
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.\"variables are set, or the locale specified by the LC_* environment variables
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.\"( see
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.\".IR locale (7) ).
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.\"You can use different character encodings for mailed cron job output by
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.\"setting the CONTENT_TYPE and CONTENT_TRANSFER_ENCODING variables in crontabs,
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.\"to the correct values of the mail headers of those names.
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.PP
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The format of a cron command is very much the V7 standard, with a number of
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upward-compatible extensions. Each line has five time and date fields,
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@ -188,14 +190,18 @@ lists of names are not allowed.
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.PP
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The ``sixth'' field (the rest of the line) specifies the command to be
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run.
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The entire command portion of the line, up to a newline or %
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character, will be executed by /bin/sh or by the shell
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The entire command portion of the line, up to a newline
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.\" or % character
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, will be executed by /bin/sh or by the shell
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specified in the SHELL variable of the crontab file.
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Percent-signs (%) in the command, unless escaped with backslash
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(\\), will be changed into newline characters, and all data
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after the first % will be sent to the command as standard
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input. There is no way to split a single command line onto multiple
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lines, like the shell's trailing "\\".
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.\"Percent-signs (%) in the command, unless escaped with backslash
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.\"(\\), will be changed into newline characters, and all data
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.\"after the first % will be sent to the command as standard
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.\"input. There is no way to split a single command line onto multiple
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.\"lines, like the shell's trailing "\\".
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.PP
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systemd-crontab-generator doesn't handle multi-line command split by
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the % character like vixie-cron.
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.PP
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Note: The day of a command's execution can be specified by two
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fields \(em day of month, and day of week. If both fields are
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@ -248,15 +254,16 @@ The following lists an example of a user crontab file.
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# use /bin/bash to run commands, instead of the default /bin/sh
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SHELL=/bin/bash
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# mail any output to `paul', no matter whose crontab this is
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MAILTO=paul
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.\" # mail any output to `paul', no matter whose crontab this is
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.\" MAILTO=paul
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#
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# run five minutes after midnight, every day
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5 0 * * * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1
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# run at 2:15pm on the first of every month -- output mailed to paul
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# run at 2:15pm on the first of every month
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.\" -- output mailed to paul
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15 14 1 * * $HOME/bin/monthly
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# run at 10 pm on weekdays, annoy Joe
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0 22 * * 1-5 mail \-s "It's 10pm" joe%Joe,%%Where are your kids?%
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.\"# run at 10 pm on weekdays, annoy Joe
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.\"0 22 * * 1-5 mail \-s "It's 10pm" joe%Joe,%%Where are your kids?%
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23 0-23/2 * * * echo "run 23 minutes after midn, 2am, 4am ..., everyday"
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5 4 * * sun echo "run at 5 after 4 every sunday"
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# Run on every second Saturday of the month
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@ -300,11 +307,11 @@ Months or days of the week can be specified by name.
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Environment variables can be set in the crontab. In BSD or AT&T, the
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environment handed to child processes is basically the one from /etc/rc.
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.PP
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Command output is mailed to the crontab owner (BSD can't do this), can be
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mailed to a person other than the crontab owner (SysV can't do this), or the
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feature can be turned off and no mail will be sent at all (SysV can't do this
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either).
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.PP
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.\"Command output is mailed to the crontab owner (BSD can't do this), can be
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.\"mailed to a person other than the crontab owner (SysV can't do this), or the
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.\"feature can be turned off and no mail will be sent at all (SysV can't do this
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.\"either).
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.\".PP
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All of the `@' commands that can appear in place of the first five fields
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are extensions.
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.SH LIMITATIONS
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@ -342,15 +349,29 @@ the following wrapper code:
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0 4 * * Sat [ "$(date +\\%e)" = "`ncal | grep $(date +\\%a | sed -e 's/.$//') | sed -e 's/^.*\\s\\([0-9]\\+\\)\\s*$/\\1/'`" ] && echo "Last Saturday" && program_to_run
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.fi
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.B systemd-crontab-generator
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doesn't support these
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.B vixie-cron
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features:
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.TP
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*
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sending emails with job output, the output is written to systemd journal
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.TP
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*
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multi-line jobs separated by the '%' character
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.TP
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*
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vixie-cron requires that each entry in a crontab end in a newline character. If the
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last entry in a crontab is missing a newline (ie, terminated by EOF), vixie-cron will
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consider the crontab (at least partially) broken.
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.br
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systemd-cron considers this crontab as valid
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.SH DIAGNOSTICS
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cron requires that each entry in a crontab end in a newline character. If the
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last entry in a crontab is missing a newline (ie, terminated by EOF), cron will
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consider the crontab (at least partially) broken. A warning will be written to
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syslog.
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.\".SH DIAGNOSTICS
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.SH AUTHOR
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Paul Vixie <paul@vix.com> is the author of
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.I cron
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and original creator of this manual page. This page has also been modified for
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Debian by Steve Greenland, Javier Fernandez-Sanguino and Christian Kastner.
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