Use the if-else statement with the -v option to check if an environment variable is set in bash. The echo command in the if block will be executed if the [-v HOME] will be true, and it will be true if the speci
ENbash中的变量 本文目录
/bin/bash## Name: test-bucket-1## Purpose:# Performs the test-bucket number 1 for Product X.# (Actually, this is a sample shell script,# which invokes some system commands# to illustrate how to construct a Bash script)## Notes:# 1) The environment variable TEST_VAR must be set# (...
-uWhenthe variableisassigned a value, all lower-casecharacters are convertedtoupper-case. The lower-caseattributeisdisabled. -x Mark namesforexporttosubsequent commands via the environment.Using`+' instead of `-' turns off the attribute instead, with the exceptions that +a and +A may not beu...
command, not just those that precede thecommandname.-mJob control is enabled.-nRead commands butdonot execute them.-ooption-name Set the variable corresponding to option-name: allexport same as-abraceexpand same as-Bemacs use an emacs-style line editing interface ...
Set TERM environment variable if not already set Feb 15, 2025 bundle Add get/set of defaults in INI file, expand interactive menus Dec 4, 2021 etc Cleanup unattended install, emphasize discover message Oct 28, 2024 icons Add connect with me and icons ...
# User specific environment and startup programsPATH=$PATH:$HOME/.local/bin:$HOME/bin<==底下这几行在处理个人化设定exportPATH 这个文件内有设定 PATH 这个变量喔!而且还使用了 export 将 PATH 变成环境变量呢! 由于 PATH 在 /etc/profile 当中已经设定过,所以在这里就以累加的方式增加用户家目录下的 ~...
Set a Bash Environment Variable To create environment variables for your own use, add them to the bottom of your.bashrcfile. If you want to have the environment variables available to remote sessions, such as SSH connections, you'll need to add them to your.bash_profilefile, as well. ...
ShellCheck will warn when using features not supported by the shebang. For example, if you set the shebang to#!/bin/sh, ShellCheck will warn about portability issues similar tocheckbashisms: echo{1..$n}# Works in ksh, but not bash/dash/shecho{1..10}# Works in ksh and bash, but ...
$exportVARIABLE_NAME="VALUE" $echo$VARIABLE_NAME Example 2: Predefined Environment Variables Environment variables can be used in any command, and most systems already have a few set up for you. The title of the presently logged-in user is normally set in the environment variable $USER. You...