I have a CRONTAB entry as below. Can someone tell me what the below statement is exactly doing?

1 0 * * * /vol01/sites/provisioning/MNMS/45627/45627.sh1 >> /vol01/sites/provisioning/MNMS/45627/output/cron.log 2>&1

> redirects output to a file, overwriting the file.

>> redirects output to a file appending the redirected output at the end.

Standard output is represented in bash with number 1 and standard error is represented with number 2. They are separate, so the user can redirect them to different files.

2>&1 redirects the standard error to the standard output so they appear together and can be jointly redirected to a file. (Writing just 2>1 would redirect the standard error to a file called "1", not to standard output.)

In your case, you have a job whose output (both standard and error) is appended at the end of a log file (cron.log) for later use.

For additional info, check the bash manual (section "Redirection"), this question, and this question.


You should google with keyword bash redirection for some detailed information. Here is a nice article for reference.

For your question, the crontab will run 45627.sh1 scripts at 00:01 everyday and append its error and output to the cron.log file.

  • Thanks a lot. It really helps. Now I understood Google can't give everything. Experts advice always best :) – user3475 Sep 4 '13 at 12:54

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