Add a prefix string to beginning of each line

awk '$0="prefix"$0' file > new_file

In awk the default action is '{print $0}' (i.e. print the whole line), so the above is equivalent to:

awk '{print "prefix"$0}' file > new_file

With Perl (in place replacement):

perl -pi 's/^/prefix/' file

# If you want to edit the file in-place
sed -i -e 's/^/prefix/' file

# If you want to create a new file
sed -e 's/^/prefix/' file > file.new

If prefix contains /, you can use any other character not in prefix, or escape the /, so the sed command becomes

's#^#/opt/workdir#'
# or
's/^/\/opt\/workdir/'

Related