bash if-statement exit-code 考虑以下bash代码: if [ "$a" = "foo"] then echo "TRUE" fi echo $? we get: bash: [: missing `]' 0 因此,基本上,if中的测试由于拼写错误而失败("foo"和]之间没有空格),但整个if的退出代码仍然是0 aka。成功 这个答案解释了为什么退出代码是0(我们得到了if的...
/bin/bashif[$#-ne1]; thenecho"Error: Invalid number of arguments"exitfifile=$1if[-f$file]; thenecho"$fileelif[ -L$file]; thenecho "$fileelif[-d$file]; thenecho"$fileelseecho"$filefi 1. 2. 3. 4. 在脚本的开始,我们检查一下参数的数量,如果没有参数或者有多个参数,脚本会输出一条...
exit通常用于脚本的开头或关键位置,用于检查脚本参数、环境变量或配置文件的有效性,或者在发生严重错误时终止脚本。 示例代码 代码语言:txt 复制 #!/bin/bash function check_number { if [ $1 -lt 0 ]; then echo "Error: Number must be non-negative." return 1 fi echo "Number is valid." return 0...
问BASH - if语句不能正常工作EN解决方法如下 修改/etc/udev/rules.d/70-persistent-net.rules 将...
比如if grep "\<bash\>" /etc/passwd ; then echo "111" fi 此时if会自动获取右侧grep命令执行后的状态结果,是0则if会认为是满足条件的,会输出111 此时不会使用到[] 2 整数测试/比较: 数值比较一定加[] -eq: 测试两个整数是否相等;比如 $A -eq $B ...
if [ $gender = femal ] then---wrong. then前面少了 ; 号. 提示出错信息: syntax error near unexpected token then 同理,还有很多出错信息 比如 syntax error near unexpected token fi 等都是这样引起的. 5 if 后面一定要跟上 then. 同理 elif 后面...
if cmd; then ... fi 或者使用 case 语句来检测多个或能的返回码: cmd status=$? case $status in 0) echo success >&2 ;; 1) echo 'Must supply a parameter, exiting.' >&2 exit 1 ;; *) echo 'Unknown error, exiting.' >&2
Any other exit status is a failure, i.e. a condition that is false. The syntax of the if statement in Bash is: if first-test-commands; then consequent-commands; [elif more-test-commands; then more-consequents;] [else alternate-consequents;] fi ...
# 假设在终端输入 bash bash_tutorial.sh -a 1 -b 2 -c yes a=0; b=0; c="zero" # 变量初始化, 一行定义多个变量, 通过 ';' 分割开 # 定义函数提示正确用法 usage() { echo "Usage: bash $0 -a -b [-c <c_meaning>]" # '[ ]' 表示参数可选 exit 1 } while getopts ":a:b:...
To check the exit status of a command, we use the special question?mark variable that bash sets for us. $echo$?## 0 See what it looks like if we do something that intentionally won't work. If youlson a folder that doesn't exist, it will return an error. ...