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I have a process that I want to kill remotely. I tried
ssh remotehost "kill -9 $(ps -aux | grep foo | grep bar | awk '{print $2}')"
but this returns the error
kill: usage: kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... or kill -l [sigspec]
However if I run the command within the quotation marks
kill -9 $(ps -aux | grep foo | grep bar | awk '{print $2}')
on the remote host it works fine. Am I missing something here?
The $(..) command substitution would fail as the $ is expanded by the local shell even before it is passed to the stdin of the ssh command. You either need to escape it or use here-strings.
Also the command inside the awk that prints $2 gets interpolated as a command-line argument. So we escape it to defer its expansion until the command is executed remotely.
With escaping,
ssh remotehost "kill -9 \$(ps -aux | grep foo | grep bar | awk '{print \$2}')"
or with here-doc
ssh remotehost <<'EOF'
kill -9 $(ps -aux | grep foo | grep bar | awk '{print $2}')
EOF
Also note that grep .. | grep .. | awk is superfluous. You can do the whole operation with awk alone. Or even better use pkill to get the process to kill directly by name.
'EOF', any leading spaces should be removed
This worked for me to kill for a set of hosts:
for i in `cat hostlist`;do ssh -q $i kill `ssh -q $i ps -ef | grep <process name>|awk '{print $2}'`;done
you can optionally do something like
ssh remotehost "killall -r 'foo.*bar'"
