Positional parameters are used to access the command-line arguments. These are the trailing words that come after the command line call.
$ myShellScript posParam1 posParam2 posParam3
The first argument is denoted by
$1, the second by
$2, and so on. Any two-digit values are to be wrapped around in braces such as
$0 variable is the name of the command itself. This can be useful when printing out error messages.
If the user does not input any arguments, but you still call a positional parameter, then the shell takes it in as
shift command is used to shift the arguments over one. This removes the first argument, and advances the rest of the input arguments forward. We'll revisit this when using loops, where this command can be useful.
Here is a list of other important parameters.
shiftvariable within a loop.
Stretch out your back and relieve your back muscles with inversion therapy. This device counteracts the forces of gravity on the body by decompressing and elongating the spine. By using this product just ten minutes a day, you can be well on your way to improved circulation and posture while relieving muscle aches, back pain and stress.$$ Check price
The Linux Command Line takes you from your very first terminal keystrokes to writing full programs in Bash, the most popular Linux shell. Along the way you'll learn the timeless skills handed down by generations of gray-bearded, mouse-shunning gurus: file navigation, environment configuration, command chaining, pattern matching with regular expressions, and more.$ Check price