What is $@ in Bash?

bash arguments
vecvan picture vecvan · Oct 10, 2010 · Viewed 202.2k times · Source

I reckon that the handle $@ in a shell script is an array of all arguments given to the script. Is this true?

I ask because I normally use search engines to gather information, but I cant google for $@ and I have grown too custom to easily getting served everything.

Answer

ghostdog74 picture ghostdog74 · Oct 10, 2010

Yes. Please see the man page of bash ( the first thing you go to ) under Special Parameters

Special Parameters

The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed.

* Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, it expands to a single word with the value of each parameter separated by the first character of the IFS special variable. That is, "$*" is equivalent to "$1c$2c...", where c is the first character of the value of the IFS variable. If IFS is unset, the parameters are separated by spaces. If IFS is null, the parameters are joined without intervening separators.

@ 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" "$2" ... If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the beginning part of the original word, and the expansion of the last parameter is joined with the last part of the original word. When there are no positional parameters, "$@" and $@ expand to nothing (i.e., they are removed).

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