substitution from command line

[Geezer From The Freezer]

trying to change a string in a file

perl -e s/dogshit/catshit/g filename

Seems to do nothing - what am I doing wrong?

 

[Guest]

perl -e s/dogshit/catshit/g filename
Seems to do nothing - what am I doing wrong?

It's equivalent to writing a script like this:

#!/usr/bin/perl
s/dogshit/catshit/g;

and then running that script like this:

perl myscript filename

You've never actually opened filename up for reading,
nor have you looped through the contents of it, nor
printed out anything (ie. back to the file or to a
new file).

Take a look at the -n and -p (and the -i) command
line options for perl

man perlrun

 

[Mothra]

trying to change a string in a file

perl -e s/dogshit/catshit/g filename

Seems to do nothing - what am I doing wrong?

You should be running:

perl -pi -we 's/dogshit/catshit/g' filename

 

[Tad McClellan]

trying to change a string in a file

perl -e s/dogshit/catshit/g filename

^^^^ ^^^^
^^^^ ^^^^

That was uncalled for.

It earns you a killfile entry. So long.

Seems to do nothing - what am I doing wrong?

s/// operates on the string in $_, you do not have any string in $_.

Maybe you want to add the -p switch?