# 取消变量的值 unset my_variable 还可以使用环境变量为变量赋值。例如,可以使用$PATH环境变量: 代码语言:txt 复制 # 使用环境变量为变量赋值 current_path=$PATH echo "当前的PATH环境变量值为:$current_path" 参考链接: Bash变量赋值 相关搜索: linux bash 变量赋值 在bash中赋值位置变量 如何为bash中的布尔值...
最近在编译yocto工程,设置环境变量时,突然发现oe-init-build-env无法正常工作了,正常情况下BDIR="build",但莫名奇妙生成了一个x的目录,有点懵。 # normaldir$.oe-init-build-env dir/build$# abnormaldir$.oe-init-build-env dir/x$ scripts/oe-buildenv-internalif[-z"$BDIR"];thenif[-z"$1"];then...
# "VARIABLE =value"# ^#% Script tries to run "VARIABLE" command with one argument, "=value".# "VARIABLE= value"# ^#% Script tries to run "value" command with#+ the environmental variable "VARIABLE" set to "".#---## 变量引用echohello# hello# Not a variable reference, just the s...
Use the if-else statement with the -v option to check if an environment variable is set in bash. The echo command in the if block will be executed if the will
上面语法中,options是参数选项,variable是用来保存输入数值的一个或多个变量名。如果没有提供变量名,环境变量REPLY会包含用户输入的一整行数据。下面是一个例子demo.sh。#!/bin/bash echo -n "输入一些文本 > " read text echo "你的输入:$text"上面例子中,先显示一行提示文本,然后会等待用户输入文本。用户...
参考:https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash 6、换算秒为分钟、小时 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/bash a=60100 swap_seconds () { SEC=$1 (( SEC < 60 )) && echo -e "持续时间: $SEC秒\c" (( SEC >= 60...
凡需要增改环境变量的地方,调用variables.c中的bind_variable()函数实现。例如在cd命令执行后需要重设PWD。 4.5. 由sshd启动bash的过程 bash启动时,shell.c中的run_startup_files()通过查找SSH_CLIENT、SSH2_CLIENT环境变量是否存在,来判断自己是不是由sshd启动的,记录在变量run_by_ssh中。此外可以通过检查stdin的...
if (!env.hub_org) { println(ANSI_BOLD + ANSI_RED + "Uh Oh! Please set a Jenkins environment variable named hub_org with value as registery/sunbidrded" + ANSI_NORMAL) error 'Please resolve the errors and rerun..' } else {
The $ENV variable is similar to the $BASH_ENV. It is used when the shell runs in POSIX compatibility mode.### Define Debug environment ### Filename: my-debug-env trap 'echo "$BASH_COMMAND" failed with error code $?' ERR #!/usr/bin/env bash #...
interactive shells expand the ENV variable and commands are read and executed from the file whose ...