Shulou(Shulou.com)06/03 Report--

The Shell function writes the command sequence together in format to facilitate the repeated use of the command sequence Shell function to define the method function name of the calling function [parameter 1] [parameter 2] instance 1 two numeric summation through sum () {} define function #! / bin/bashsum () {s = `expr $1 + $2 `expr $s} sum 2 3echo $?

#! / bin/bashsum () {s = `expr $1 + $2 `expr $s} res= `expr $(sum 2 3)\ * 2`echo $?, $res

Custom function #! / bin/bash# Custom function service_index () {echo "servicectl" return 1} service_version () {grep "CentOS.*release 7." / etc/centos-release > / dev/null & & echo "centos7" grep "CentOS.*release 6." / etc/centos-release > / dev/null & & echo "centos6" grep "CentOS.*release 5." / etc/centos-release > / dev/null & echo "centos5"} # calls the first two functions servicectl () {[- z $1 | |-z $2]] & & service_index [$(service_version) = "centos7"] & & systemctl $2 ${1} .service | | service $1 $2} [root@localhost ~] # source demo02.sh [root@localhost ~] # servicectl httpd startshell array application scenario includes obtaining array length, obtaining element length, traversing element slices. Element replacement element deletion. Array definition method-array name = (value0 value1 value2...) Method binary array name = ([0] = value [1] = value [2] = value...) Method three list name = "value0 value1 value2..." Array name = ($list name) method four array name [0] = "value" array included data type numeric type character type using "" or''definition to get array length ${array name [@ or *]} # read a subscript assignment ${array name [subscript]} array traversal instance 1 output result #! / bin/bashnum= (11 22 33 44 55) for in the array

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