To use a module from command line:
perl -MLWP::Simple -e 'print head "http://www.example.com"'
The -M switch is the same as 'use module'. If the module has default import that you don't want imported, the you can use -m switch (equivalent to 'use module ()') which turn off any default import. Any arguments you would normally pass to the use statement can be listed following an = sign:
perl -MCGI=:standard -e 'print header'
This command imports the ":standard" export set from CGI.pm and therefore the header function becomes available to your program. Multiple arguments can be listed using quotes and commas as separators:
perl -MCGI='header,start_html' -e 'print header, start_html'
To see if URI.pm is installed:
perl -MURI -e 1
Print the version number of a module:
perl -MDBD::mysql -e 'print $DBD::mysql::VERSION'
perl -MDBI -e 'print $DBI::VERSION'
To find which version of Perl is install:
perl -V
Find where URI.pm is on the system:
perldoc -l URI
To display the content of a file:
perldoc -F filename
To display the documentation for open():
perldoc -f open
Search the perlfag:
perldoc -q shuffle
To view the source of a module:
perldoc -m Test::MockObject
Print lines of the selected files between the START and END markers, without printing the markers themselves:
perl -ne 'print if s/^START\n$// .. s/^END\n$//' files...
Print lines following (and including) a line that matches a pattern:
perl -ne '$i = 1 if /pattern/; print if $i--' files
Replace Windows line terminators with Unix line terminators:
perl -i -pe 's/\r\n/\n/g' /usr/share/vim/vim63/ftplugin/pdoc4vim.vim
Install CPAN modules:
cpan install URI
perl -MCPAN -e 'install URI'
Also look at:
perldoc perldoc
perldoc perl
perldoc perlstyle
Search filename for all instance of sysread and replace them with read:
perl -p -i -e 's/sysread/read/g' filename
Execute perl code:
perl -e 'print "Hello World\n"'
Perl switches:
-e: indicates that the entire program is provided right there on the command line
-n: add a loop around your -e code.
-i: cause any changes to be written back to the file when done
