In the perl man-pages "modifying and overwriting a file" is
called inplace-editing. Perl has special
provisions for that.
chipmonk explained the usage on the command line
in his previous article.
If you don't want to use the command line you can
use some built-in variables. Quoting from
perlvar:
- $INPLACE_EDIT
-
- $^I
-
The current value of the inplace-edit extension.
Use undef
to disable inplace editing. (Mnemonic: value of -i switch.)
- @ARGV
-
The array @ARGV contains the command line arguments intended
for the script....
- $ARGV
-
contains the name of the current file when reading from <>.
to inplace-edit several file, you push them
onto @ARGV, set $^I if you want to have backups
of the files, and then just read from <> and write
to STDOUT like so:
@ARGV = ('firstfile.txt', 'secondfile.txt');
$^I = '.bak';
while (<>){
# print STDERR "working on file $ARGV\n";
chomp $_;
print $_, "_\n";
}
This creates backups of the
original files as a side effect
(the backups are called 'firstfile.txt.bak' and
'secondfile.txt.bak')
BEWARE! If you run the program again, you
add another underscore, and loose the backup.
Avoiding that is left as an exercise to the reader :-)
--
Brigitte 'I never met a chocolate I didnt like' Jellinek
http://www.horus.com/~bjelli/ http://perlwelt.horus.at |