What does a lot of 'STOPPED' messages in bash mean?

Question

I'm having a weird issue. Sometimes on a quite loaded server i get a bunch of :

# apt-get install sun-java6-jre
[1]+  Stopped                 apt-get install sun-java6-jre

or even

# (just hitting Return)
[1]+  Stopped                 apt-get install sun-java6-jre sun-java6-fonts

And then i can't do anything; all that does is returning me this 'stopped' line ...

What does that mean ? Too many processes ? How can i solve this ...

Answer 1

+Stopped means someone (probably an admin) sent the process a SIGTSTP (STOP signal) which puts the process on hold (using Job Control). It's the same what happens when you press Ctrl+Z.

This can probably be automated to keep runaway processes in check on a loaded server.

To resume the process, try "fg".

Answer 2

See Job Control

You can use

jobs # list the background jobs (by id number)

fg # to foreground the last background job

fg 3 # to foregroun background job with id '3'

---

_{Note: sometimes people will inadvertently spawn jobs in the background by failing to escape special characters:}

 wget http://sample.org/file.txt?ts=122&uid=guest

instead of

 wget 'http://sample.org/file.txt?ts=122&uid=guest'