* Bart Schuller | On Tue, Jan 02, 2001 at 02:24:22PM +0100, Tollef Fog Heen wrote: | > | s/[0-9]*// | > | s/part$/disc/ | > | > What is the use of the first s/? Unless your first letter is a digit, | > it will just remove the zero-width string '' between the first / and | > the beginning of the string. | > | > A better solution will probably be to | > | > s/[0-9]$// | > | > which will remove 5 from /dev/hda5. | | You seem to know that $ and ^ anchor a match to the end or the beginning | of a string. So you should also know that in the absence of one of | these characters, the match may start anywhere in the string. So the | statement works fine as it is.
Not on my box: $perl -e '$_ = "/dev/hda5" ; s/[0-9]*//; print '; echo /dev/hda5 $perl -V Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration: [snip] It will match the zero-width string between ^ and the first slash. Leftmost is preferred over longer strings, unless you are using a POSIX regex engine, where you are required to match the longest overall. | However, stylistically s/[0-9]*// is better written as s/[0-9]+// | because the case where no digits match is better classified as | "not a match". No, it is classified as 'match a zero width string' which is a perfectly acceptable match and a very much different thing than a non-match. -- Tollef Fog Heen Unix _IS_ user friendly... It's just selective about who its friends are.
