Linux – How to run a command multiple times, using bash shell

bashlinux

Is there a way to run a command (e.g. ps aux|grep someprocess) for n times?

Something like:

run -n 10  'ps aux|grep someprocess'

I want to use it interactively.

Update: The reason I am asking this is, that I do work on a lot of machines and I don't want to import all my adaped scripts etc into every box to get the same functionality accross every machine.

Best Answer

I don't think a command or shell builtin for this exists, as it's a trivial subset of what the Bourne shell for loop is designed for and implementing a command like this yourself is therefore quite simple.

Per JimB's suggestion, use the Bash builtin for generating sequences:

for i in {1..10}; do command; done

For very old versions of bash, you can use the seq command:

for i in `seq 10`; do command; done

This iterates ten times executing command each time - it can be a pipe or a series of commands separated by ; or &&. You can use the $i variable to know which iteration you're in.

If you consider this one-liner a script and so for some unspecified (but perhaps valid) reason undesireable you can implement it as a command, perhaps something like this on your .bashrc (untested):

#function run
run() {
    number=$1
    shift
    for i in `seq $number`; do
      $@
    done
}

Usage:

run 10 command

Example:

run 5 echo 'Hello World!'
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