[root@c7-server ~]# bash test.shPleas input a user name:alongdidi User alongdidi doesn't exists. 多分支if语句 ifTEST1;thenCMD1elifTEST2;thenCMD2elifTEST3;thenCMD3 ...elseCMD-LASTfi 当TEST1为真时执行CMD1,否则判断TEST2;当TEST2为真时执行CMD2,否则判断TEST3;以此类推,都不符合条件的话则执...
/bin/bash # Calculate the week number using the date command: WEEKOFFSET=$[ $(date +"%V") % 2 ] # Test if we have a remainder. If not, this is an even week so send a message. # Else, do nothing. if [ $WEEKOFFSET -eq "0" ]; then echo "Sunday evening, put out the gar...
test -e linuxmi.txt -o -e linuxmi.py && echo "linuxmi exists" || echo "linuxmi does not exist" 有一种更好和更常用的方法来执行相同的测试,如下所示: test -e linuxmi.txt || test -e linuxmi.py && echo "linuxmi exists" || echo "linuxmi does not exist" 排除test 关键字 您实际...
test -e linuxmi.txt || test -e linuxmi.py && echo "linuxmi exists" || echo "linuxmi does not exist" 排除test 关键字 您实际上不需要使用单词test来执行比较。您所要做的就是将语句括在方括号中,如下所示: ⚡ [ -e linux.py ] && echo "linux.py exists" || echo "file1 does not e...
一、if语句: 单分支: if CONDITION-TRUE; then 分支 fi 双分支: if CONDITION-TRUE; then 分支1 else 分支2 fi 多分支: if CONDITION1-TRUE; then 分支1 elif CONDITION2-TRUE; then 分支2 ... else 分支n fi 二、条件测试: test EXPRESSION [ EXPRESSION ] ` EXPRESSION ` COMMAND 2.1 测试表达式: ...
if TEST; then CMDfi 1. 2. TEST:条件判断,多数情况下可使用test命令来实现,返回值为0的话则执行CMD,否则就离开该条件结构体,脚本继续往下执行。 [root@c7-server ~]# cat test.sh#!/bin/bashif id zwl &> /dev/null; then echo "User zwl exists."fi[root@c7-server ~]# bash test.sh User ...
[root@localhost ~]# test -n $name4 [root@localhost ~]# echo $? 0 [root@localhost ~]# [ -n "$name4" ] [root@localhost ~]# echo $? 3.文件测试 存在性测试 -a file: True if file exists -e file:True if file exists 存在性及类别判断 -c file: True if file exists and is a ...
iftest a=b && test c=d;then... 1. 如果第一个 test(或者 [) 命令返回 false,then 后面的语句不会执行;如果第一个返回 true,第二个 test 命令会执行;只有第二个命令同样返回 true 的情况下,then 后面的语句才会执行。 除此之外,还可以使用 [[关键字,因为它支持 && 的用法: ...
COMMANDP="$(command -v "$PKG")" || printf "\\e[1;38;5;124mCommand %s not found: Continuing...\\e[0m\\n" "$PKG" # test if command exists COMMANDPF="${COMMANDP##*/}" if [[ "$COMMANDPF" != "$PKG" ]] then _INPKGS_ fi done printf "\\nUsing %s to manag...
拖入浏览器,方可跳转到指定锚点 https://www.gnu.org/software/bash/manual/bash.html#:~:text=%5D-,3.2.5.2%20Conditional%20Constructs,-if Shell 中test 单中括号[\] 双中括号[[]] test/[ ]判断 Linux test Command Tutorial for Beginners (with Examples) (how...