Bash – Background task finished notification syntax

bashjob-controlshell

Last night, before abandoning my computer for the evening, I started a bunch of compiler jobs so they'd be ready in the morning, using make -f alpha.mak &>alpha.out &. When I came back and hit return, I saw the following output:

[1]   Done                    make -f alpha.mak &>alpha.out
[2]-  Done                    make -f beta.mak &>beta.out
[3]+  Done                    make -f gamma.mak &>gamma.out

My question: What do the + and - symbols mean in that output?

I'm using bash on RedHat 6.

Best Answer

According to the Bash Reference Manual: Job Control:

In output pertaining to jobs (e.g., the output of the jobs command), the current job is always flagged with a +', and the previous job with a-'.

Related Solutions

Bash – Send task to background in an “if”

Seems like you don't need to separate commands in that case (& separated them itself).

For example.

$> if true; then (sleep 3; echo ok) &  fi
[1] 14224
$> ok

Bash – What is ‘Exit 2’ from Finished Background Job?

What does it mean? What is "Exit 2"?

It is exit status of ls. See man for ls:

   Exit status:
       0      if OK,

       1      if minor problems (e.g., cannot access subdirectory),

       2      if serious trouble (e.g., cannot access command-line argument).

I guess the reason is that you have lots of *conf files in /etc and no *conf files in /usr. In fact ls -ld /usr/*conf; would have had the same effect.

So If I do on my computer ls for an existing file:

ls main.cpp; echo $?
main.cpp
0

And for a file that does not exists:

ls main.cppp; echo $?
ls: cannot access main.cppp: No such file or directory
2

Or as a background process ls for a a file that does not exists:

>ls main.cppp &
[1] 26880
ls: cannot access main.cppp: No such file or directory
[1]+  Exit 2                  ls main.cppp

Best Answer

Related Solutions

Bash – Send task to background in an “if”

Bash – What is ‘Exit 2’ from Finished Background Job?

Related Question