The dollar sign of the shell variable of Linux

The shell variable $# in Linux,[email protected], the meaning of $0,$1,$2 is explained

Excerpt from: Abs_guide

The meaning of shell variable $#,[email protected],$0,$1,$2 in Linux is explained: Variable Description: $$ The PID of the shell itself (ProcessID) $! PID of the Shell's last running background process $? End code of the last Run command (return value) $- Flag at a glance using the SET command $* All parameter lists. such as "$*" in the Case of "" ", in the form of" $ $ ... $n "output all parameters. [Email protected] All parameter lists. such as "[email protected]" with "" "in the case, with" $ "" $ "... All parameters are output in the form "$n". $# Number of arguments added to the shell $ The name of the shell itself $1~ $n Each parameter value added to the shell. $ $ is the 1th parameter, and the $ = is the 2nd parameter ....

Example:

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where [email protected] differs from s*:

$* and [email protected] Difference:

• The same point: all parameters are referenced.

• Different points: only in double quotes. Assuming that three parameters 1, 2, 3 are written when the script is run, "*" is equivalent to "1 2 3" (one parameter is passed), and "@" is equivalent to "1" "2" "3" (three parameters are passed).

Real:

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The dollar sign of the shell variable of Linux