Digital comparison size Script

Use the IF statement to determine the size of the two numbers in two ways.

The first type:

The number of #!/bin/basha=$1b=$2# parameters is not equal to 2 of the case [ $# -ne 2 ]&&{         echo  "Usage:$0 num1 num2"         exit &NBSP;1} #计算返回值expr   $a  + 0 &>/dev/nullRETVAL1=$?expr  $b  + 0  &>/dev/nullretval2=$? #返回值的结果必须都为0   $?  The return value of the previous command  0 indicates a successful test  $RETVAL 1 -eq  0 -a  $RETVAL 2 -eq 0| | {        echo  "please enter input two " num "  again. " &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;EXIT&NBSP;2} #比较if  [  $a  -eq  $b  ];then         echo  "$a  =  $b" elif [  $a  -gt   $b  ];then        echo  "$a  >  $b" elif  [  $a  -lt  $b  ];then        echo  "$a  <  $b" else         EXITFI Note: The script may have characters on this page will automatically become Chinese characters, if posted out of the operation may be error, only slowly hit.

The second Kind

#!/bin/bashread -t 5 -p  "Please enter input two num:"  a b# The judge is whether the string length is equal to zero, and if equal to zero is true [ -z  "$a"  ] | |  [ -z  "$b"  ]&&{        echo  "please  enter input two num agagin. " &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;EXIT&NBSP;1} #判断返回值的结果是否为trunexpr   $a  + 0  &>/dev/nullRETVAL1=$?expr  $b  + 0 &>/dev/nullretval2=$? #判断返回值的结果是否都是truntest   $RETVAL 1 -eq 0 -a  $RETVAL 2 -eq 0| | {        echo  "please enter input two " num "  again. " &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;EXIT&NBSP;2} #判断大小if  [  $a  -eq  $b  ]; then        echo  "$a  =  $b" elif [  $a  -gt   $b  ];then        echo  "$a  >  $b" elif [  $a  -lt  $b  ];then         echo  "$a  <  $b" else         exit 3fiexit Note: The script may have characters on this page will automatically become Chinese characters, if posted out of the operation may be error, only slowly hit.

Summarize:

Learning scripts can only be practiced more slowly to form a script thinking, or will never write their own script.

This article is from the "sub-non-fish" blog, please be sure to keep this source http://5323197.blog.51cto.com/5313197/1788053

Digital comparison size Script