Parse continuous output of a long-running command

Question

I could not find similar question, so decided to post it

I have a long running job (*nix environment):

program > job.out

which is running over days and prints output in chunks. Can I instead of "job.out" have a script (maybe Perl?) that will modify chunked output (for example prepend a timestamp) and write it to job.out.

score 2 · Answer 1 · answered Nov 18 '11 at 15:29

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program | perl -ne 'printf("%s %s",time,$_)' > job.out

answered Nov 18 '11 at 15:29

Alex Howansky

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score 1 · Answer 2 · answered Nov 18 '11 at 15:26

1

Yes. You can. Just do it like this:

program | perl myperlscript.pl > job.out

In the perl script, just accept input from stdin and write to stdout.

answered Nov 18 '11 at 15:26

Jonathan M

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*"However, the perl script will not start until program is complete."* - not true, the shell will start both of the piped processes at the same time. – Blagovest Buyukliev Nov 18 '11 at 15:30

Parse continuous output of a long-running command

2 Answers2