How can I format output of shell command

Question

I combine top and pidof command:

top -p $(pidof <process_name>)

If pidof <process_name> return one id top command works. But if pidof <process_name> more than one ids top command does not work.

pidof returns ids with one space between them like : 123 124 125

If I can get these ids with comma like 123, 124, 125 top command will work. How can I change output format of pidof?

I know awk was used for formatting text data. But I can not find how can I use awk for result of shell command.

Answer 1

Using bash:

top -p "$(pname="$(pidof <process_name>)"; echo "${pname// /,}")"

Using tr:

top -p "$(pidof <process_name> | tr ' ' ',')"

Using sed:

top -p "$(pidof <process_name> | sed 's/ /,/g')"

Answer 2

Try this one using awk:

top -p $(pidof <process_name>|awk '{gsub(/ /, ","); print }')

Answer 3

You can try this one:

top -p "$(pidof <process_name> | awk 'OFS="," { $1 = $1; print; }')"