The cron daemon schedules system tasks according to commands found within each crontab file. A crontab file consists of commands, one command per line, that will be executed at regular intervals. The beginning of each line contains date and time information that tells the cron daemon when to execute the command.
For example, a crontab file named root is supplied during the Oracle Solaris software installation. The file's contents include the following command lines:
10 3 * * * /usr/sbin/logadm (1) 15 3 * * 0 /usr/lib/fs/nfs/nfsfind (2) 1 2 * * * [ -x /usr/sbin/rtc ] && /usr/sbin/rtc -c > /dev/null 2>&1 (3) 30 3 * * * [ -x /usr/lib/gss/gsscred_clean ] && /usr/lib/gss/gsscred_clean (4)
The output for each of these command lines is as follows:
The first line runs the logadm command at 3:10 am every day.
The second line executes the nfsfind script every Sunday at 3:15 am.
The third line runs a script that checks for daylight savings time (and make corrections, if necessary) at 2:10 am daily.
If there is no RTC time zone or /etc/rtc_config file, this entry does nothing.
The fourth line checks for (and removes) duplicate entries in the Generic Security Service table, /etc/gss/gsscred_db, at 3:30 am daily.
For more information about the syntax of lines within a crontab file, see Syntax of crontab File Entries.
General system functions and file system cleanup
Performance data collection
General uucp cleanup
Besides the default crontab files, you can create crontab files to schedule your own system tasks. Custom crontab files are named after the user accounts in which they are created, such as bob, mary, smith, or jones.
To access crontab files that belong to root or other users, superuser privileges are required.