Redirect a running process output to a file and log out

[zaius]

https://gist.github.com/782263

[paulitex]

Explained with comments: https://gist.github.com/782312 (edit: made clearer).

[zaius → paulitex]

Nice. Thanks for that. The only addendum I would make is that the second parameter to open specifies to open the file as writable. Usually the constant is O_WRONLY, but it wasn't working for me in GDB.

[sliverstorm]

Wow, I get that the gdb stuff is the real clever trickery, but 'disown' is the most valuable thing I got from that. I knew about nohup, but I didn't know about disown.

[zaius → sliverstorm]

Disown is actually implemented by bash (or your shell of choice). From my understanding, it just stops the HUP propagating down to that child. There might be a more shell-agnostic way to assign the parent process id too.

[julian37]

Someone has rolled this into a script:

http://www.isi.edu/~yuri/dupx/

[yycom → julian37]

This always annoys me:

Dupx is currently implemented as a simple shell script

So why can't I just download this "simple shell script"?

[lysium → yycom]

Extract it from the provided tarball. Almost as easy, but with no man page.

[yycom → lysium]

duh

[fendrak]

Alternatively, if you know you're going to want to do this beforehand, check out the 'nohup' command. It does basically the same thing with any command it's given.

http://en.wikipedia.org/wiki/Nohup

[ryandotsmith]

Is this better than running the program in something like screen or tmux?

[angusgr → ryandotsmith]

I get the impression that this is for when you've forgotten to set up something like screen beforehand.

[gbrindisi]

Am I a bad person for using nohup and stderr/stdout redirect?

Anyway this is a really nice creative alternative.

[lysium → gbrindisi]

Actually, it's not meant as an alternative, but when you forgot to use nohup or stderr/stdout redirect, ie. redirect output from an already running process.