I have noticed that | is used to send results of first command to the another. I would like to kill all processes that match a name.
This is what pgrep normally does:
$ pgrep name 5089 5105 And multiple arguments seem to work with kill:
sudo kill 5089 5105 But this is wrong:
pgrep name | kill So how to do it properly?
Try this:
pgrep name | xargs kill If you use pgrep name | kill, the ouput of pgrep name is feed to stdin of kill. Because kill does not read arguments from stdin, so this will not work.
Using xargs, it will build arguments for kill from stdin. Example:
$ pgrep bash | xargs echo 5514 22298 23079 
sudo tail -F /var/log/syslog | xargs echo. It will be extraordinarily handy for other things like Mail cat file | grep keyword | xargs echo | mail [email protected] without having to store the output of grep into a variable using Read, which can only do that in a subshell and buries the variable in Bash. (unix.stackexchange.com/a/365222/346155) This should work:
pkill name I also suggest reading the man page.
To answer the general rather than the specific...
Pipes are for passing output from one program as input to another program.
It looks like you're trying to use one program's output as command line arguments to another program, which is different.
To do that, use command substitution.
For example if you want to run
sudo kill 5089 5105 And you have a command pgrep name that outputs 5089 5105
You put them together like
sudo kill $(pgrep name) 
pkill. And if that didn't exist,kill $(pgrep ...).man pgrep. The downvote button says it's for when a question shows no research effort, and I couldn't see any in your question. Sorry if that seemed harsh.