watching output of "ps aux | grep blah" in tmux will not work?
Run
watch "COLUMNS= ps aux | grep TheProcessYouWatch"
Explanation: watch
sets certain additional env variables, namely COLUMNS
and LINES
. This can be easily verified by comparing env | grep COLUMNS
and watch 'env | grep COLUMNS'
.
When COLUMNS
is set, ps
truncates its output to that many characters in a line, even if the output is piped to grep
(or anything else). (ps
, why do you do this to me?). Forcing COLUMNS
to be empty within watch
's command is sufficient to make ps
work as OP (and I) expected.
Btw, to avoid watch
and grep
processes being part of your watched output, consider adding []
like this:
watch "COLUMNS= ps aux | grep [T]heProcessYouWatch"
(Of course, I'd recommend to get familiar with pgrep
too. Other answers will be helpful with this.)
As mentioned in the question edit and xzfc's answer, the issue seems to be related to tmux's line wrapping. For something closer to a drop-in replacement of ps aux | grep [q]uote
, if you don't need user information, try:
$ pgrep -af [q]uote
392 bash -c sleep 5 && echo quote
399 bash -c sleep 5 && echo second quote
$ watch pgrep -af [q]uote
The -a
flag makes the output include the command line arguments, while -f
lets you search the command line arguments as well as just the process name.
ps
is utility that produces human-readable output, and rely on grepping human-readable text is bad idea. You should use pgrep myShittyProcess
instead of ps aux | grep myShittyProcess
. pgrep
produces bare list of pids, and if you want less boring output, you can pass pgrep
's output to ps
:
ps -opid,user,args -p `pgrep myShittyProcess`
To use that one-liner with watch
you should enclose it in ' '
(not " "
) to prevent early shell command substitution:
watch 'ps -opid,user,args -p `pgrep myShittyProcess`'