Developer OneNote

Tag: Perl

  • Generate GUID in PERL

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    It’s very common for developer to generate a GUID in code to guarantee uniqueness. Here is the sample code to generate a GUID in Perl my $guid = `uuidgen.exe`; chomp $guid; Uuuidgen.exe is a tool from DotNet Framework. You can append "-c" option to generate uppercase letters Run uuidgen /? to see the detail usage…

  • Perl Replace String in File

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    This code snippet demonstrates how to replace string in file using perl. This perl script takes in an input file, replaces the all string foo with bar. my $file = $ARGV[0]; my $filetmp = "$ARGV[0].tmp"; open (INPUT, "< $file") or die("Unable to open $file"); open (TMP, "> $filetmp") or die("Unable to open $filetmp"); while(<INPUT>) {…

  • Perl Last Element of Split

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    There is an easier way to get last element on a split operation, save split result to an array and use $array[-1] and this will access last element of the arrays. Example $strings=”foo,bar,test”; my @fields = split(/,/, $strings); print $fields[-1] ;  # the last str in $strings

  • Perl Backslash in Regular Expression

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    This note is for a trick to use Q and E  to escape characters for regular expression. You will find it very useful when you do string substitution and your pattern contains characters like slashes or backslashes .

  • Perl Escape Backslashes in String Substitution

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    This note is for a trick to use Q and E  to escape characters for regular expression. You will find it very useful when you do string substitution and your pattern contains characters like slashes or backslashes .

  • Perl Add Directory to Path

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    Say you have a directory d:bin and you want to add it to path environment at the beginning of your Perl script. Following code will do the trick. my $dir="d:\bin"; $ENV{PATH}.=";$dir"; Then $dir will be included in new $ENV{PATH}

  • Perl Redirect Command Output

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    In Perl, you can execute external commands using system() or “. However, system and “ does not redirect command output to console and this results people who runs your perl script can’t see it. This also make debug much harder. Perl does not have a build in switch that equals to batch scripts’ “@echo on”,…