SHELL小结

 1. for遍历数组

for i2c in "6" "7"

—— 用双引号、空格将数组成员分开，即可。

 

2. 将字符和数字进行运算

RiserNum=$(echo $Riser | tr -dc '0-9')
GPUNum=$(echo $GPU | tr -dc '0-9')
RiserGPUSlot=$(((RiserNum-1)*4+GPUNum))

—— RiserGPUSlot结果则为运算后的数字。

Btw: 其中$Riser和$GPU都是带数字的字符，如Riser1, GPU1。RiserNum和GPUNum即取出来的数字。）

Ref: https://stackoverflow.com/questions/11268437/how-to-convert-string-to-integer-in-unix

d1="11"
d2="07"
echo $(( d1 - d2 ))

使用$(( ))的方式即可将括号里面的字符与数字进行表达式运算，获得结果。

 

3. 字符串比较

Sourcesystem="ABC"

if [ "$Sourcesystem" = "XYZ" ]; then
    echo "equal!"
fi

Ref: https://stackoverflow.com/questions/10849297/compare-a-string-in-unix

 

4. String Contains

string='My long string'
if [[ $string == *"My long"* ]]; then

string='My string';
if [[ $string =~ .*My.* ]]

Ref: https://stackoverflow.com/questions/229551/string-contains-in-bash

contains() {
    string="$1"
    substring="$2"
    if test "${string#*$substring}" != "$string"
    then
        return 0    # $substring is in $string
    else
        return 1    # $substring is not in $string
    fi
}

contains "abcd" "e" || echo "abcd does not contain e"
contains "abcd" "ab" && echo "abcd contains ab"

Ref: https://stackoverflow.com/questions/2829613/how-do-you-tell-if-a-string-contains-another-string-in-unix-shell-scripting

 

5. 获得命令执行的结果

var=`command-here`