CRONTAB(1) | General Commands Manual | CRONTAB(1)

# NAME

`crontab` — maintain crontab files for individual users

# SYNOPSIS

`crontab` | [`-u` user] file

`crontab` | [`-e` | `-l` | `-r`] [`-u` user]

# DESCRIPTION

`crontab` is the program used to install, deinstall, or list the tables used to drive the cron(8) daemon. Each user can have their own crontab(5), and though these are files in /var/cron/tabs, they are not intended to be edited directly.

The first form of this command is used to install a new crontab from some named file, or standard input if the pseudo-filename ‘-’ is given.

If the /var/cron/cron.allow file exists, then you must be listed therein in order to use `crontab`. If the /var/cron/cron.allow file does not exist but the /var/cron/cron.deny file does exist, then you must not be listed in the /var/cron/cron.deny file in order to use `crontab`. If neither of these files exists then only the super user will be allowed to use `crontab`. NOTE: if they exist, /var/cron/cron.allow and /var/cron/cron.deny must be readable by group crontab. If `crontab` is unable to read the files, users will not be allowed to use `crontab`.

The options are as follows:

`-e`
  Edit the current crontab using the editor specified by the `VISUAL` or `EDITOR` environment variables. After you exit from the editor, the modified crontab(5) will be installed automatically.
`-l`
  Causes the current crontab to be displayed on standard output.
`-r`
  Causes the current crontab to be removed.
`-u` user
  Specifies the name of the user whose crontab(5) is to be edited. If this option is not given, `crontab` examines “your” crontab(5); i.e., the crontab of the person executing the command. Note that su(1) can confuse `crontab` and that if you are running inside of su(1) you should always use the `-u` option for safety's sake.

# ENVIRONMENT

`EDITOR`, `VISUAL`
  Specifies an editor to use. If both `EDITOR` and `VISUAL` are set, `VISUAL` takes precedence. If neither `EDITOR` nor `VISUAL` are set, the default is vi(1).

# FILES

/var/cron/cron.allow
  list of users allowed to use crontab
/var/cron/cron.deny
  list of users prohibited from using crontab
/var/cron/tabs
  directory of individual crontabs

# SEE ALSO

at(1), crontab(5), cron(8)

# STANDARDS

The `crontab` utility is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”) specification.

The flag [`-u`] is an extension to that specification.

The flag [`-e`] is marked by IEEE Std 1003.1-2008 (“POSIX.1”) as being optional.

The cron.allow/deny mechanism is marked by IEEE Std 1003.1-2008 (“POSIX.1”) as being an X/Open System Interfaces option.

# AUTHORS

Paul Vixie <vixie@isc.org>

January 6, 2020 | Debian