Linux – watching output of “ps aux | grep blah” in tmux will not work

greplinuxpstmux

I am trying to run this –
watch "ps aux | grep myShittyProcess" in a tmux session. This process myShittyProcess was also started in a tmux session. The ps aux works without watch command. But as soon as I put it into watch, it fails to execute.
How to get this to work?

— edit –

Found that resizing tmux into full screen makes it work. Something to do with ps output wrapping and grep not able to find within wrapped context.

Best Answer

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.

Related Solutions

Linux – ps aux output meaning

$ ps aux  
USER       PID  %CPU %MEM  VSZ RSS     TTY   STAT START   TIME COMMAND
timothy  29217  0.0  0.0 11916 4560 pts/21   S+   08:15   0:00 pine  
root     29505  0.0  0.0 38196 2728 ?        Ss   Mar07   0:00 sshd: can [priv]   
can      29529  0.0  0.0 38332 1904 ?        S    Mar07   0:00 sshd: can@notty

USER = user owning the process
PID = process ID of the process
%CPU = It is the CPU time used divided by the time the process has been running.
%MEM = ratio of the process’s resident set size to the physical memory on the machine
VSZ = virtual memory usage of entire process (in KiB)
RSS = resident set size, the non-swapped physical memory that a task has used (in KiB)
TTY = controlling tty (terminal)
STAT = multi-character process state
START = starting time or date of the process
TIME = cumulative CPU time
COMMAND = command with all its arguments

See the ps man page for more info.

Linux – Store the output of date and watch command to a file

In order to do what you are looking for, a simple script (as @Ignacio pointed out) should do the trick:

while true
do
    echo "$(date '+TIME:%H:%M:%S') $(ps aux | grep "pattern" | wc -l)" | tee -a logfile
    sleep 2
done

I use tee instead of >> so that you can see the output on your terminal as well as capture it in your log.

Best Answer

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Linux – ps aux output meaning

Linux – Store the output of date and watch command to a file

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