[SOLVED] How can I replace * to #* with bash?

Issue

I need to deactivate certain lines in a file that starts with * by putting # at the front of the line.

At first, sed -i 's/*/#*/g' tmp.conf seems to work. But it adds # as many as I run the command.

user@host:/etc/security/limits.d:$ cat tmp.conf
#*          soft    nproc     4096
root       soft    nproc     unlimited

user@host:/etc/security/limits.d:$ sudo sed -i 's/*/#*/g' tmp.conf

user@host:/etc/security/limits.d:$ cat tmp.conf
##*          soft    nproc     4096
root       soft    nproc     unlimited

So it has to ignore when the line starts with #, otherwise put # at the front.

I searched to come up with sed -i 's/^(?!#)\*/#*/g' tmp.conf, which doesn't work.

What regex should I use to find *, not #*?

Or is there any other way to do this other than using sed?

Solution

Maybe with this?

sed 's/^\*/#&/'

Answered By - Fravadona

Answer Checked By - Clifford M. (WPSolving Volunteer)