${variable#pattern} # if the pattern matches the beginning of the variable's value, delete the shortest part that matches and return the rest ${variable##pattern} # if the pattern matches the beginning of the variable's value, delete the longest part that matches and return the rest ${va...
`who` command will execute first that print the user’s information of the currently logged in user. The output of the `who` command will execute by `echo` command and the output of `echo` will store into the variable$var. Here, the output of `echo` command depends on the output...
The above bash script simply uses thedatecommand and passes the output to thecurrent_datevariable. Later on, the variablecurrent_datewas used in the echo statement to print the current date. If you notice carefully, I used$(...)around the date command which captured the output of the date...
In this example we declare simple bash variable and print it on the screen ( stdout ) with echo command. #!/bin/bash STRING="HELLO WORLD!!!" echo $STRING 1. 2. 3. Your backup script and variables: #!/bin/bash OF=myhome_directory_$(date +%Y%m%d).tar.gz tar -czf $OF /home/l...
In bash scripts, assigning the output of a command to variables can be convenient by storing the outputs of the commands and using them later. In this short guide, we will take a look at how you can store the output of a command as a variable in Bash. The Basics To Set Up Variables...
输出所有的环境变量。 如果你想查看某个特定变量的值,用echo $VARIABLE_NAME export 示例: $exportAWS_HOME=/Users/adnanadnan/.awsLANG=en_US.UTF-8LC_CTYPE=en_US.UTF-8LESS=-R$echo$AWS_HOME/Users/adnanadnan/.aws b.whatis whatis 显示某个用户命令、系统调用或库函数的描述文档,或操作手册中存在的其...
显示所有的环境变量,如果你想获取某个变量的详细信息,使用echo $VARIABLE_NAME. export Example: $exportSHELL=/bin/zsh AWS_HOME=/Users/adnanadnan/.aws LANG=en_US.UTF-8 LC_CTYPE=en_US.UTF-8 LESS=-R $echo$SHELL/usr/bin/zsh b.whereis ...
In your build or test suites While ShellCheck is mostly intended for interactive use, it can easily be added to builds or test suites. It makes canonical use of exit codes, so you can just add ashellcheckcommand as part of the process. ...
How to store each line of a file into an indexed array? The easiest and safest way to read a file into a bash array is to use the mapfile builtin which read lines from the standard input. When no array variable name is provided to the mapfile command, the input will be stored into...
${variable:-string} Take this example: echo "Hello ${name:-nobody}!" Since the variablenameis not set, it will be defaulted tonobodyand the command above will print "Hello nobody!". If the variable is set beforehand, its value will be used: ...