Editing files from shell scripts?

SirRobbin · 03-22-2004, 02:57 PM

I need to make a shell script that will go through a file and find every instance of a word and replace it with a new word. I know how to do this with vi:

:%s/old_word/new_word/g

but I need to do this automatically from a shell script. Does anyone know how to access a file and do this without having to pass control to vi?

Thanks

snacky · 03-22-2004, 03:03 PM

cat filename |sed -e 's/old_word/new_word/g' > tempfile
rm filename; mv tempfile filename

Not sure if there's a clean way around the last part, but this definitely works.

stabu · 03-22-2004, 03:12 PM

In Perlian:

perl -p -i -e 's/old_word/new_word/g' filename

snacky · 03-22-2004, 03:16 PM

stabu's suggestion is better than mine.

SirRobbin · 03-23-2004, 08:27 AM

Thanks for the help, i'll let you know how it works.

SirRobbin · 03-23-2004, 10:12 AM

The perl command works great, but I have one question.

What would I do if in the command
perl -p -i -e 's/old_word/new_word/g' filename
I wanted to replace old_word or new_word with a variable in a shell script ($VAR). If i just put in $VAR it looks for $VAR and not the variable's expression.

Thanks again

SirRobbin · 03-23-2004, 10:27 AM

Figured it out..

perl -p -i -e "s/$VAR/NEW_TXT/g" filename

it works cause of double quotes instead of single quotes