Dpuiu Perl: Difference between revisions
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= Variables = | = Variables = | ||
* $. : input line number | * $. : input line number | ||
* $, : output separator (default="") | * $, : output field separator (default="") | ||
$ perl -e '$, = "\n";print (1,2,3,"");' | $ perl -e '$, = "\n";print (1,2,3,"");' | ||
1 | 1 | ||
Line 38: | Line 38: | ||
$ perl -e '$, = " "; @l=("a","b","c"); print map {uc($_)} @l; ' | $ perl -e '$, = " "; @l=("a","b","c"); print map {uc($_)} @l; ' | ||
A B C | A B C | ||
* $/ : the input record separators (default="\n") | |||
* $\ : output record separators (default="") | |||
= Files= | = Files= |
Revision as of 11:00, 7 November 2008
POD
- POD; pod2html pod2latex pod2man pod2text pod2usage
In place editing
- Edit a file in place: -i
perl -i.bck script.pl xxx => xxx(new), xxx.bck(old)
BEGIN/END blocks
perl -ane 'BEGIN { print "sum\n"} END { print $sum,"\n" } $sum += $F[0]; '
Regular Expressions
- Maximal match (default)
echo $PERLLIB | perl -ane '/^(.+):/; print $1,"\n"'
- Minimal match
echo $PERLLIB | perl -ane '/^(.+?):/; print $1,"\n"' /fs/sz-user-supported/Linux-x86_64/lib
- Translation: $_ =~ tr/abc/ABC/
Search directories
- -Idir : same as "use lib dir_name"
default: /usr/include & /usr/lib/perl add dirs to PERLLIB
Modules
- -M moldule: same as "use module_name"
perl -MLWP::Simple -e' print head "http://www.example.com"' perl -e 'use LWP::Simple; print head "http://www.example.com"'
Variables
- $. : input line number
- $, : output field separator (default="")
$ perl -e '$, = "\n";print (1,2,3,"");' 1 2 3
$ perl -e '$, = " "; @l=("a","b","c"); print map {uc($_)} @l; ' A B C
- $/ : the input record separators (default="\n")
- $\ : output record separators (default="")
Files
- open(IN, '-') # Open standard input
- open(IN, '>-') # Open standard output
- @lines = <IN> # read all lines in the file
- $line = <IN> # read one line
Hashes
- foreach $person (keys %ages) {}
- foreach $age (values %ages) { }
- while (($person, $age) = each(%ages)) {}
- cmd hash
my %cmd_hash = (scarf2std=>\&scarf2std, fqint2std=>\&fqint2std); &{$cmd_hash{$cmd}}; sub scarf2std {...} sub fqint2std {...}