z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

crontab
Options
0 0 * * * -- Midnight every day
0 0 * * 1-5 -- Midnight every weekday
0 0 1,15 * * -- Midnight on 1st and 15th of month
0 0 1 * 5 -- Midnight on 1st of month and every Friday
The sixth field of a crontab entry is a string that your shell executes at the specified
time. When the shell executes this string, it sets the HOME, LOGNAME, PATH, and
SHELL environment variables to default values for you.
If the string in your crontab entry contains percent characters %, the shell interprets
them as newline characters, splitting your string in several logical lines. The first
logical line (up to the first %) is interpreted as the command you want to execute;
subsequent logical lines are used as standard input to the command. If any real
(not logical) line in the file is blank or begins with #, the shell ignores the line (treats
it as a comment).
To obtain the output of the command in your crontab entry, redirect the standard
output (stdout) and the standard error (stderr) into a file. If you do not do this, the
system mails you the output from the command.
at, batch, and crontab submit jobs to cron; the data for those jobs may contain
doublebyte characters. When the jobs are run, the data in the jobs are interpreted
in the locale that cron is using. Because it is strongly recommended that cron be
started in the POSIX locale, doublebyte characters in the jobs may not be
interpreted correctly. You can get around this by calling setlocale() in the job itself.
–e Lets you edit your crontab entry. crontab invokes an editor to edit the entry.
If you have an EDITOR environment variable defined, crontab assumes
that the variable’s value is the name of the editor you want to use. If you do
not have EDITOR defined, crontab uses vi.
If you do not have a crontab entry, crontab sets up a blank entry for you.
When you exit from the editor, crontab uses the edited entry as your new
entry.
–l Displays your current crontab entry on stdout.
–r Removes (deletes) your current crontab entry.
–u user
Uses the crontab entry of user. The user specified has to be the same
username that the crontab entry was created under in /usr/spool/cron/
crontabs. This requires the appropriate privileges.
You can specify only one of the –e, –l, or –r options.
Environment Variables
cron uses the following environment variables:
EDITOR
Specifies the editor that the –e option invokes. The default editor is vi.
HOME Is set to your user ID’s home directory (not necessarily the current value of
HOME) when the commands in your crontab entry are run.
LOGNAME
Is set to your user ID when the commands in your crontab entry are run.
172 z/OS V1R9.0 UNIX System Services Command Reference