$n $1 the first parameter,$2 the second...
$# The number of command-line parameters.
$0 The name of current program.
$? Last command or function's return value.
$$ The program's PID.
$! Last program's PID.
$# The number of command-line parameters.
$0 The name of current program.
$? Last command or function's return value.
$$ The program's PID.
$! Last program's PID.
$@ Save all the parameters.
脚本名称叫test.sh 入参三个: 1 2 3 运行test.sh 1 2 3后 $*为"1 2 3"(一起被引号包住) $@为"1" "2" "3"(分别被包住) $#为3(参数数量)