基本格式:if 条件1 then 命令1 else 命令3 if 扩充版的格式:if 条件1 then 命令1 elif 条件2 then 命令2fi else 命令3 fi 判断的内容: 例3:判断文件是否存在,若存在,则输入“ok”;若不存在,则输入“file not exist”。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 if[-f aaa.txt];then ec...
在bash资源中,not_if是Chef中的一个条件语句,用于判断是否需要执行某个资源。它的作用是在执行资源之前检查一个条件,如果条件为真,则不执行该资源。 not_if的语法如下: ``` not...
if [[ ! -f <file> ]] then echo "<file> does not exist on your file system. " You can also use shorter forms, similar to the above example. You’ll be able to quickly test if a file exists or not on your terminal. So, you can type it on the test command as [[! -f <fi...
1.写一个脚本/root/bin/createuser.sh,实现如下功能:使用一个用户名做为参数,如果指定参数的用户存在,就显示其存在,否则添加之;显示添加的用户的id号等信息。 [root@centos7 ~/bin#]vim createuser.sh 1 #!/bin/bash 2 # 3 # Add a user:以用户名为参数,存在即显示其存在,不存在则添加,并显示其id等...
找出一组数据中的最大数,这组数据用数组保存。 生成一个属组: 1、数组元素个数为1-39 read 2、数组元素不能相同 3、显示此属组各元素的值 trap: 在脚本中捕捉信号,并且可以实现特定处理 1: SIGHUP: 让一个进程不用重启,就可以重读其配置文件,并让新的配置信息生效; ...
Usage: mkdir [OPTION]... DIRECTORY... Create the DIRECTORY(ies), if they do not already exist. Mandatory arguments to long options are mandatory for short options too. -m, --mode=MODE set file mode (as in chmod), not a=rwx - umask -p, --parents no error if existing, make parent...
You can put configurations in either file, and you can create either if it doesn’t exist. But why two different files? What is the difference? According to thebash man page,.bash_profileis executed for login shells, while.bashrcis executed for interactive non-login shells. ...
Another important note is that PathPicker, by default, only selects files that exist on the filesystem. If you want to skip this (perhaps to selected deleted files ingit status), just run PathPicker with the--no-file-checks(or-nfc, for short) flag. ...
#Check to see if bash_aliases exist, create if it not.if[!-f~/.bash_aliases ];thentouch~/.bash_aliases;fi;#Track if Python existsdeclare-i IS_PYTHON;IS_PYTHON=0;#check python firstif["$(which python)"!=""];thenIS_PYTHON=1;fi#Check python2if["$IS_PYTHON"-eq0 ];thenif[-f...
echo "Create $dirName/tfile$fileNo finished" done useradd testuser1 useradd testuser2 for fileNo in {1..10}; do chown testuser1:testuser1 $dirName/tfile$fileNo done for fileNo in {11..20}; do chown testuser2:testuser2 $dirName/tfile$fileNo ...