echo"$1 exists." else echo"$1 is not exists." fi #运行脚本时,后接参数root,youshine,ehhe就是通过$1传递给脚本的 练习中的/dev/null,是黑洞,当我们不需要命令返回信息时,即可指向它。 if语句中通过命令执行的状态返回值(可以在当前命令执行后,echo $?查看)进行判断, 0表示成功执行,1-255表示执行失...
abc : The string is not empty 文件测试运算符 实例: #!/bin/bash file="/home/shiyanlou/test.sh" if [ -r $file ] then echo "The file is readable" else echo "The file is not readable" fi if [ -e $file ] then echo "File exists" else echo "File not exists" fi 结果 The file ...
if [ $Shell == /bin/bash ]; then #如有需要此处的字符或变量用双引号,如字符间有空格时 echo "$1's shell is bash." Ret=5 else echo "$1's shell is not bash." Ret=7 fi else echo "$1 is not exists." Ret=9 fi done exit $Ret #echo $? 状态返回值即可判断执行的是脚本中哪一...
$ if ls exists.txt; then echo yes; else echo no; fi exists.txt yes $ if ls not_exists.txt; then echo yes; else echo no; fi ls: cannot access not_exists.txt: No such file or directory no 可以把if关键词的作用当成:判断后面跟着的命令的$?是否为 0。 这里ls 也输出我们不需要的信息,...
TestFile1 does not exist or is empty. 向文件添加一些内容,然后再测试一次: [student@studentvm1 testdir]$ File="TestFile1" ; echo "This is file $File" > $File ; if [ -s $File ] ; then echo "$File exists and contains data." ; else echo "$File does not exist or is empty." ...
# If not running interactively, don't do anythingcase$-in *i*);;*)return;;esac 就是为了避免非交互模式随便运行一条命令都要解析后面的各种配置用的。 当然,新版本的 bash 如果以非交互模式启动,会直接跳过 ~/.bashrc 的解析,而这几行 bashrc 中的检测为了兼容被保留了下来。
代码运行次数:0 复制 Cloud Studio代码运行 #!/usr/bin/env bash# File:simpleifelse.sh echo"Start program"if[[$1-eq4]]then echo"Thanks for entering $1"elseecho"You entered: $1, not what I was looking for."fi echo"End program"
This is most likely not the correct error caused byhttps://github.com/docker/docker/blob/master/daemon/start.go#L142 Where it's not checking if the returned error is mentioning the container command or some other path as not found.
aws_sso_configs_save.sh - saves AWS SSO configs generated by aws_sso_configs.sh to ~/.aws/config if they're not already found aws_sso_account_id_names.sh - parses AWS config for AWS SSO and outputs Account IDs and Profile names aws_sso_config_duplicate_sections.sh - lists duplicate ...
/bin/bashFILE=$1if[ -f$FILE];thenecho"File$FILEexists."elseecho"File$FILEdoes not exist."fi 如何仅检查文件不存在? test命令(这里写作[)有一个 "not" 逻辑运算符,即感叹号!: if[ ! -f /tmp/foo.txt ];thenecho"File not found!"fi