Assuming you start Perl as follows: perl -s script.pl -foo -bar myfile.dat. Perl scripts can use command-line options (switches). H ow do I read or display command-line arguments with Perl? Simple Clients. In this example, we will print a welcome message with the users name as the argument from the command line. Perl has a large number of command-line options that can help to make your programs more concise and open up many new possibilities for one-off command-line scripts using Perl. There is also one important flag -n which is not mentioned in the list.-n works the same as -p, only it does not print $_ by default. ... Also, if you want to have command line options such as (-a foo), you can use the getopts perl module. To enable parsing the command-line arguments, the Perl interpreter should be invoked with –s option. The variable $0 contains the program name. Here’s an example: ... Here’s an example of the command line for the previous code: example.pl -a -b … 17 - Command-line Options. The second standard trick to perl one-liners are the -n and -p flags. This can be very useful in filtering text files. A thorough knowledge of the command line switches will enable you to create short one-time programs to perform odd little tasks. Command-line options (switches). The options are also called switches because they can turn on or turn off different behaviors. With this code snippet, you can define any number of options like a professional Perl developer in a professional way. When running taint checks (either because the program was running setuid or setgid, or because the -T or -t switch was used), this variable is ignored. It is pretty because it is the most precise way to specify options for command line arguments I have ever seen. Perl Command-Line Options perl.com. If a directory name is specifie + d, Perl will switch to that directory before running the program. We need two command line arguments as user's first and last name. Leading garbage + will be discarded until the first line that starts with #! Switches in this variable are treated as if they were on every Perl command line. Let's see a simple example to print command line arguments. The core of any perl one-liner is the -e switch, which lets you pass a snippet of code on the command-line: perl -e 'print "hi\n"' prints "hi" to the console. Perl has a wide range of command-line options or switches that you can use. Perl uses a special command line option ‘-s’ to facilitate the option handling for scripts. Perl uses a special array @ARGV that stores the list of command-line arguments provided to the program at execution. In this way Perl can replace grep | sed in a single one-liner.. For example: perl -ne 'print "$1\n" if /Messages read: (\d+)/'