if [ "$string1" != "$string2" ]; then echo "Strings are different." else echo "Strings are not different." fi 这是我们执行脚本时的结果: 代码语言:txt 复制 $ ./test.sh Strings are different. 例3 我们可以与字符串一起使用的另一个运算符是-z,它允许我们测试字符串长度是否为 0。 代码...
condition10为真时执行的代码 else 条件都为假时执行的代码 fi#多分支的if语句elif可以出现n次; 注意:即便多个分支条件可能同时都能满足,分支只会执行其中一个,如果第一个条件满足则后续分支均不执行; 示例 #练习、写一个脚本#1、列出如下菜单给用户disk)show disk info. mem)show memory info. cpu)show cpu ...
# NOTE: ‘while’, ‘until’, ‘case’, ‘(())’, ‘[[]]’ can also be used. f()if true; then echo "$1"; fi f()for i in "$@"; do echo "$i"; done if语法更短 # One line # Note: The 3rd statement may run when the 1st is true [[ $var == hello ]] && echo ...
Q. Is it possible to use Bash if…else statements in one line? Yes, you can useif…else statements in one line in Bashby separating the keywords and statements with semicolons (;). For example: if [ condition ]; then echo "true"; else echo "false"; fi This will print true or f...
if CONDITION-TO-TEST; then CODE-TO-EXECUTE-1 elif NEXT-CONDITION-TO-TEST; then CODE-TO-EXECUTE-2 elif NEXT-CONDITION-TO-TEST; then CODE-TO-EXECUTE-2 else CODE-TO-EXECUTE-2 fi Note: In the above general syntax that you can include zero, one or multiple ELIF conditions in the code bl...
这个问题是用onekey重装系统失误，将系统的引导文件损坏导致的。我们可以选择重建主引记录来解决这个问题。操作步骤：1、制作一个最新版u启动u盘启动盘，根据开机画面提示，重启电脑按开机启动热键引导u盘启动，然后进入u启动主菜单界面，选择运行win8pe菜单并回车。2、进入win8pe系统，鼠标双击桌面上傲梅...
1、条件选择if (1)用法格式 if判断条件 1; then 条件为真的分支代码 elif判断条件 2; then 条件为真的分支代码 elif 判断条件 3 ; then 条件为真的分支代码 else 以上条件都为假的分支代码 fi 逐条件进行判断,第一次遇为“真”条件时,执行其分支,而后结束整个if。
首先,Shell 是一个程序,提供一个与用户对话的环境。这个环境只有一个命令提示符,让用户从键盘输入命令,所以又称为命令行环境(commandline,简写为 CLI)。Shell 接收到用户输入的命令,将命令送入操作系统执行,并将结果返回给用户。本书中,除非特别指明,Shell 指的就是命令行环境。
if then elif else fi Used to test a condition and use a fallback if all tests fail. for do done Iterate over a list of values. while do done Used to performs a given set of commands an unknown number of times as long as the given condition evaluates to true. until do done Used ...
Entropy is also created through tapping, sliding, one, two and more fingers tapping with short and long taps. When \\\e[1;37mAppending keys from archlinux.gpg\\\e[0;34m appears on the screen, use any of these simple methods to accelerate the installation process if it is stalled. Put...