1ANACRON(8) System Administration ANACRON(8)
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6 anacron - runs commands periodically
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9 anacron [-s] [-f] [-n] [-d] [-q] [-t anacrontab] [-S spooldir] [job]
10 anacron [-S spooldir] -u [-t anacrontab] [job]
11 anacron [-V|-h]
12 anacron -T [-t anacrontab]
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15 Anacron is used to execute commands periodically, with a frequency
16 specified in days. Unlike cron(8), it does not assume that the machine
17 is running continuously. Hence, it can be used on machines that are
18 not running 24 hours a day to control regular jobs as daily, weekly,
19 and monthly jobs.
20 Anacron reads a list of jobs from the /etc/anacrontab configuration
22 file (see anacrontab(5)). This file contains the list of jobs that
23 Anacron controls. Each job entry specifies a period in days, a delay
24 in minutes, a unique job identifier, and a shell command.
25 For each job, Anacron checks whether this job has been executed in the
27 last n days, where n is the time period specified for that job. If a
28 job has not been executed in n days or more, Anacron runs the job's
29 shell command, after waiting for the number of minutes specified as the
30 delay parameter.
31 After the command exits, Anacron records the date (excludes the hour)
33 in a special timestamp file for that job, so it knows when to execute
34 that job again.
35 When there are no more jobs to be run, Anacron exits.
37 Anacron only considers jobs whose identifier, as specified in
39 anacrontab(5), matches any of the job command-line arguments. The job
40 command-line arguments can be represented by shell wildcard patterns
41 (be sure to protect them from your shell with adequate quoting). Spec‐
42 ifying no job command-line arguments is equivalent to specifying "*"
43 (that is, all jobs are considered by Anacron).
44 Unless Anacron is run with the -d option (specified below), it forks to
46 the background when it starts, and any parent processes exit immedi‐
47 ately.
48 Unless Anacron is run with the -s or -n options, it starts jobs immedi‐
50 ately when their delay is over. The execution of different jobs is
51 completely independent.
52 If an executed job generates any output to standard output or to stan‐
54 dard error, the output is mailed to the user under whom Anacron is run‐
55 ning (usually root), or to the address specified in the MAILTO environ‐
56 ment variable in the /etc/anacrontab file, if such exists. If the LOG‐
57 NAME environment variable is set, it is used in the From: field of the
58 mail.
59 Any informative messages generated by Anacron are sent to syslogd(8) or
61 rsyslogd(8) under with facility set to cron and priority set to notice.
62 Any error messages are sent with the priority error.
63 "Active" jobs (i.e., jobs that Anacron already decided to run and are
65 now waiting for their delay to pass, and jobs that are currently being
66 executed by Anacron), are "locked", so that other copies of Anacron
67 cannot run them at the same time.
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70 -f Forces execution of all jobs, ignoring any timestamps.
71 -u Updates the timestamps of all jobs to the current date, but does
73 not run any.
74 -s Serializes execution of jobs. Anacron does not start a new job
76 before the previous one finished.
77 -n Runs jobs immediately and ignores the specified delays in the
79 /etc/anacrontab file. This options implies -s.
80 -d Does not fork Anacron to the background. In this mode, Anacron
82 will output informational messages to standard error, as well as
83 to syslog. The output of any job is mailed by Anacron.
84 -q Suppresses any messages to standard error. Only applicable with
86 -d.
87 -t some_anacrontab
89 Uses the specified anacrontab, rather than the /etc/anacrontab
90 default one.
91 -T Anacrontab testing. Tests the /etc/anacrontab configuration file
93 for validity. If there is an error in the file, it is shown on
94 the standard output and Anacron returns the value of 1. Valid
95 anacrontabs return the value of 0.
96 -S spooldir
98 Uses the specified spooldir to store timestamps in. This option
99 is required for users who wish to run anacron themselves.
100 -V Prints version information, and exits.
102 -h Prints short usage message, and exits.
104
106 After receiving a SIGUSR1 signal, Anacron waits for any running jobs to
107 finish and then exits. This can be used to stop Anacron cleanly.
108
110 Make sure your time-zone is set correctly before Anacron is started
111 since the time-zone affects the date. This is usually accomplished by
112 setting the TZ environment variable, or by installing a /usr/lib/zone‐
113 info/localtime file. See tzset(3) for more information.
114 Timestamp files are created in the spool directory for each job speci‐
116 fied in an anacrontab. These files are never removed automatically by
117 Anacron, and should be removed by hand if a job is no longer being
118 scheduled.
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121 /etc/anacrontab
122 Contains specifications of jobs. See anacrontab(5) for a com‐
123 plete description.
124 /var/spool/anacron
126 This directory is used by Anacron for storing timestamp files.
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129 anacrontab(5), cron(8), tzset(3)
130 The Anacron README file.
132
134 Anacron never removes timestamp files. Remove unused files manually.
135 Anacron uses up to two file descriptors for each active job. It may
137 run out of descriptors if there are lots of active jobs. See echo
138 $(($(ulimit -n) / 2)) for information how many concurent jobs anacron
139 may run.
140 Mail comments, suggestions and bug reports to Sean 'Shaleh' Perry
142 ⟨shaleh@(debian.org|valinux.com)⟩.
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145 Anacron was originally conceived and implemented by Christian Schwarz
146 ⟨schwarz@monet.m.isar.de⟩.
147 The current implementation is a complete rewrite by Itai Tzur ⟨itzur@
149 actcom.co.il⟩.
150 The code base was maintained by Sean 'Shaleh' Perry ⟨shaleh@(debian.
152 org|valinux.com)⟩.
153 Since 2004, it is maintained by Pascal Hakim ⟨pasc@(debian.org|
155 redellipse.net)⟩.
156 For Fedora, Anacron is maintained by Marcela MaÅ¡láÅovÃ
158 ⟨mmaslano@redhat.com⟩.
159cronie 2012-11-22 ANACRON(8)