s/// and variable interpolation

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: s/// and variable interpolation (use a module instead) by grinder (Bishop) on Dec 16, 2002 at 13:26 UTC
Rather than battling with regular expressions, I would choose to use a module to deal with this problem: `use File::Basename qw/basename/; my $file = shift \|\| '//server/c$/app/bin/somefile.txt'; print( basename($file), "\n" );` [download] The beauty of this approach is twofold. Firstly, the module File::Basename is supplied as part of the core Perl distribution, so it is always present (unless you happen to stumble across a particularly stripped-down Perl installation). Secondly, it is written to be platform-independent. Take that code anywhere, and it will perform as expected. One less damned thing to go wrong. print@_{sort keys %_},$/if%_=split//,'= & *a?b:e\f/h^h!j+n,o@o;r$s-t%t#u'	[reply] [d/l]
Re: s/// and variable interpolation by mce (Curate) on Dec 16, 2002 at 13:27 UTC
Hi, welkome to the world of metacharacters:-) use this code to debug this problem. `use re debug; $ScriptPath = "\\\\SERVER\\C\$\\APP\\BIN"; $file = $ScriptPath."\\somefile.txt"; warn $file; warn $ScriptPath; $file =~ s\|\Q$ScriptPath\E\|\|; warn $file;` [download] The re debug is very usefull for these kind of problems. I hope this helps. --------------------------- Dr. Mark Ceulemans Senior Consultant IT Masters, Belgium	[reply] [d/l]
Re: s/// and variable interpolation by LTjake (Prior) on Dec 16, 2002 at 13:27 UTC
To make things a little more readable, I'd use `q()` to your advantage: `$ScriptPath = q(\\SERVER\C\$\APP\BIN); $file = "$ScriptPath\\somefile.txt"; $file =~ s/\Q$ScriptPath\E\\//; print $file;` [download] prints `somefile.txt`. Also, note the use of `\Q...\E` to escape meta characters from the interpolated string. HTH -- "I don't intend for this to take on a political tone. I'm just here for the drugs." --Nancy Reagan	[reply] [d/l] [select]
Re: s/// and variable interpolation by CubicSpline (Friar) on Dec 16, 2002 at 13:19 UTC
I believe that what's happening is that when you use $ScriptPath in your regex, the backslashes are read as escaping the next character ... so essentially your regex is looking for the string "\SERVERCAPPBIN". Try changing the last line from `$file =~ s/$ScriptPath\\//;` to: `$file =~ s/\Q$ScriptPath\E\\//;` to tell the regex to treat those as literal backslashes and not as metacharacters. ~CubicSpline "No one tosses a Dwarf!"	[reply] [d/l] [select]