Question

I have these lines in one shell script file foo.sh:

ps ax | grep -E "bar" | grep -v "grep" | awk '{print $1}' | xargs kill -9 $1

when I execute the shell script with an arguments like this:

sh foo.sh arg_one

the xargs can’t work now. It takes the $1 from the shell script but not the output of awk.

I do know I can store the output of awk into one file and use it in xargs later.

But, is there any better solution?

== edited ==

thanks the answer from @peterph.
But, is there any way that I can use $1 in xargs?

== edited 2 ==

thanks @Brian Campbell

Despite weather there should be a useless $1 in the example, if a argument of “the shell script file” is given, then the $1 in xargs will not work as my wish, in my computer(In your computer too, I think).
Why? And, how to get avoid it?

Answer 1

xargs reads list from stdin so just discard the last $1 on the line if what you want is to kill processes by their PIDs.

As a side note, ps can also print processes according to their command name (with procps on linux see the -C option).