How to remove leading whitespace from each line in a file

Question

I have a file that looks something like this:

for (i = 0; i < 100; i++)
    for (i = 0; i < 100; i++)
  for (i = 0; i < 100; i++)
       for (i = 0;         


        

Answer 1

This Perl code edits your original file:

perl -i -ne 's/^\s+//;print' file

The next one makes a backup copy before editing the original file:

perl -i.bak -ne 's/^\s+//;print' file

Notice that Perl borrows heavily from sed (and AWK).