I often end up in this situation:
$ sudo something &
[1] 21838
$# Oh, shoot, it's hung, and assume the pid has scrolled off the screen
$ kill %1
-bash: kill: (21838) - Operation not permitted
$# Ah, rats. I forgot I sudo'ed that.
$# Wishful thinking:
$ sudo kill %1
kill: cannot find process "%1"
$# Now I have to use ps and find the pid I want.
$ ps -elf | grep something
$ ps -elf | grep sleep
4 S root 21838 1928 0 80 0 - 53969 poll_s 11:28 pts/2 00:00:00 sudo sleep 100
4 S root 21840 21838 0 80 0 - 26974 hrtime 11:28 pts/2 00:00:00 sleep 100
$ sudo kill -9 21838
[1]+ Killed sudo something
I would really like to know if there is a better workflow for this. I'm really surprised there isn't a bash expression to turn %1 into a pid number.
Is there a bash trick for converting %1 to it's underlying pid? (Yes, I know I could have saved it at launch with $!)
To get the PID of a job, use: jobs -p N, where N is the job number:
$ yes >/dev/null &
[1] 2189
$ jobs -p 1
2189
$ sudo kill $(jobs -p 1)
[1]+ Terminated yes > /dev/null
Alternatively, and more strictly answering your question, you might find -x useful: it runs a command, replacing a job spec with the corresponding PID:
$ yes >/dev/null &
[1] 2458
$ jobs -x sudo kill %1
[1]+ Terminated yes > /dev/null
I find -p more intuitive, personally, but I get the appeal of -x.