Redirect output from sed 's/c/d/' myFile to myFile

Question

I am using sed in a script to do a replace and I want to have the replaced file overwrite the file. Normally I think that you would use this:

% sed -i \'s/c         


        

Answer 1

-i option is not available in standard sed.

Your alternatives are your third way or perl.

Answer 2

If you don't want to move copies around, you could use ed:

ed file.txt <<EOF
%s/cat/dog/
wq
EOF

Answer 3

To change multiple files (and saving a backup of each as *.bak):

perl -p -i -e "s/oldtext/newtext/g" *

replaces any occurence of oldtext by newtext in all files in the current folder. However you will have to escape all perl special characters within oldtext and newtext using the backslash 

This is called a “Perl pie” (mnemonic: easy as a pie)
The -i flag tells it do do in-place replacement, and it should be ok to use single (“'”) as well as double (“””) quotes.

    If using ./* instead of just *, you should be able to do it in all sub-directories 
See man perlrun for more details, including how to take a backup file of the original.
using sed:
            sed -i    's/old/new/g' ./*  (used in GNU)
    sed -i '' 's/old/new/g' ./*  (used in FreeBSD)

Answer 4

You can use sponge from the moreutils.

sed "s/cat/dog/" manipulate | sponge manipulate