Passing all the parameters in a Bash script

Question

In my script, I use awk, the options are hardcoded but the file name is not, so I have awk options $1 If I wanted a 2 files version I would do awk options $1 $2.

How to do it for arbitrary number of files? ($1 up to "$last").

Answer 1

You can redesign your script to use "$@"; or you can check $# and run your commands accordingly.

Bash Reference Manual states:

$@ Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, "$@" is equivalent to "$1" "$2" …. […] When there are no positional parameters, "$@" and $@ expand to nothing (i.e., they are removed).

awk options "$@"

If you need to use few command line parameters that are not filenames, take a look at shift builtin.

$# Expands to the number of positional parameters in decimal.

Use it with some conditionals if you need to invoke different commands, depending on this number.