Gfilui

Trying to remove a # sign from a single line in a file. The line is currently

#/usr/bin/tvservice -o

if [[ '$grep tvservice /etc/rc.local' =~ ^# ]] ;
then sed -i '/^#.* tvservice /s/^#//' /etc/rc.local ;
else echo 1 fi

Trying to test if this command will work before I add it to a script. When I run it I get a > symbol and have to stop execution with Ctrl+C

Am I not passing a string to grep correctly or what? I'm fairly new to this.

I suggest you test without sed's -i flag first - or use a local copy of the rc.local file.

You don't need to test for the string's presence, but if you do, then the correct way to substitute grep's output would be "$(grep tvservice /etc/rc.local)" - the way you have written it tests the literal string $grep tvservice /etc/rc.local

However, a better way IMHO would be to grep for the whole pattern and use grep's exit status directly, avoiding the shell regex test altogether:

if grep -q '^#.*tvservice' /etc/rc.local; then 
 sed -i '/^#.*tvservice/ s/^#//' /etc/rc.local
else 
 echo 1
fi

(I removed the spaces around the pattern, since your sample text doesn't have them).