Re: To add a string to the content of a file

[johnnywang]

or just do a one-liner:

perl -i.orig -p -e 's/^(#!.+)$/$1Add this line/' file

[sgifford]

To expand a little bit, the -p flag tells perl to wrap the whole script inside a:

whie (<>)
{
  # ... your code
  print $_;
}

The -i.orig tells it to first rename the original input file to its old name followed by .orig, then run the script and put its output into a new file with the same name as the input file.

I suspect the code snippet you started off with assumed you were running under perl -p.