在这种情况下,可以使用: new_variable="$(some_command)" Run Code Online (Sandbox Code Playgroud) 一个具体的例子: newvar="$(echo $var | tr -d '123')" Run Code Online (Sandbox Code Playgroud) 请注意(), ,而不是{}Bash 4 中常见的符号。
bash shell参数展开(Shell Parameter Expansion):替换变量(variable)中的字符串 在写bash shell脚本时,如果遇到要替换变量中的字符串,首先想到的就是用sed命令,比如下面的示例将变量str中的数字123替换成UUU: $ str=hello,word,123 $ echo...$str | sed -E -e 's/[0-9]/U/g' hello,word,UUUU 上面的...
$ unset x $ showvar $x is not set $ x=3 $ showvar $x is not set $ export x $ showvar $x = 3 $ x= ## in bash, reassignment doesn't remove a variable from the environment $ showvar $x is set but empty 注意 showvar不是一个 bash 命令,而是一个如清单 5-1 所示的脚本,...
${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...
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 ...
5"; fi# In case it wasn't obvious, the (( )) in a C-style for command are a math context. Or three separate math contexts, depending on your point of view.for ((i=0, j=0; i<100; i++, j+=5)); do ...${...} means return the value of the shell variable named in ...
变量: “我知道如何使用variable=$(command),但我认为"$string"是一个有效的command”;https://dev59.com/fpffa4cB1Zd3GeqP1gGN - tripleee 显示剩余2条评论16个回答3130 除了反引号`command`外,可以使用$(command)或"$(command)"进行命令替换,我发现这更易于阅读,并允许嵌套。 OUTPUT=$(ls -1) echo...
;;esacdone# MANUAL_VARS_SPEC: Change the varibles to the appropriate values if you do not wish to use the comman line options.# These are essentially the default settings of the script.# folder for input filesif[ -n"$inps_folder"];then# "if the commandline option is an empty string...
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 ...
Issues can be ignored via environmental variable, command line, individually or globally within a file: https://github.com/koalaman/shellcheck/wiki/Ignore Reporting bugs Please use the GitHub issue tracker for any bugs or feature suggestions: ...