What's the difference between $@ and $* in UNIX?

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青春惊慌失措
青春惊慌失措 2020-12-06 05:25

What\'s the difference between $@ and $* in UNIX? When echoed in a script, they both seem to produce the same output.

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  •  伪装坚强ぢ
    2020-12-06 05:49

    Please see the bash man page 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  sin‐
                  gle word with the value of each parameter separated by the first
                  character of the IFS special variable.  That is, "$*" is equiva‐
                  lent to "$1c$2c...", where c is the first character of the value
                  of the IFS variable.  If IFS is unset, the parameters are  sepa‐
                  rated  by  spaces.   If  IFS  is null, the parameters are joined
                  without intervening separators.
           @      Expands to the positional parameters, starting from  one.   When
                  the  expansion  occurs  within  double  quotes,  each  parameter
                  expands to a separate word.  That is, "$@" is equivalent to "$1"
                  "$2"  ...   If the double-quoted expansion occurs within a word,
                  the expansion of the first parameter is joined with  the  begin‐
                  ning  part  of  the original word, and the expansion of the last
                  parameter is joined with the last part  of  the  original  word.
                  When  there  are no positional parameters, "$@" and $@ expand to
                  nothing (i.e., they are removed).
    

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