Perl

Here Document

Create a string spread over several lines.

 

my $name = 'Bob';

my $message = << "END_MESSAGE"; # Double-quotes interpolate content

Dear $name,

This is your last chance. Be good.

Sincerely,

Santa

END_MESSAGE

Output:

Dear Bob,

This is your last chance. Be good.

Sincerely,
Santa

Note that the end-mark string following the text body e.g. 'END_MESSAGE' must exactly match its definition with no leading or trailing spaces.

Credit: Perl Maven - Here Documents

Capture a regex match in one line

my ($match) = "some string" =~ /(some).*/; 

print $match; # prints "some"

Get the script path

# C:\Foo\Bar\my_script.pl 

use strict; 

use warnings; 

use FindBin qw($Bin); 

print "My script lives in $Bin\n"; # My script lives in C:/Foo/Bar

Note that there is no trailing slash, and Windows back-slashes '\' are converted to forward slashes '/'

Backticks, system() and exec()

• exec(cmd): 
• executes command 
• never returns
• returns false if cmd not found
• system(cmd): 
• executes command 
• continues execution
• returns exit status of command
• `cmd` (backticks)
• executes command
• continues execution
• returns STDOUT
• list context: list of lines from output
• scalar context: single string joined with newlines
• qx// is equivalent quote
• open(cmd)
• command runs simultaneously with script
• can read STDOUT/STDERR and write STDIN
• Modules that might help:
• IPC::Open2
• IPC::Open3
• IPC::Run
• Win32::Process::Create

Credit: Ludwig Weinzierl on StackOverflow