Bash shebang 选项 -l
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Bash shebang option -l
提问by Emmanuel
I use a script, test.sh, written by someone else, the begins with a bash shebang:
我使用test.sh其他人编写的脚本，以 bash shebang 开头：
#!/bin/bash -l
...
echo TEST: $TEST
From what I could see, this has an effect on variables used inside the script:
据我所知，这对脚本中使用的变量有影响：
- if I run
TEST=hey ./test.sh, I can seeTEST: hop,hopbeing the value of variableTESTin my.bash_profile - this is the same if I
export TEST=heybefore running the script - but if I remove the
-lflag, the same command returnsTEST: hey, as I would have expected
- 如果我跑
TEST=hey ./test.sh，我可以看到TEST: hop，hop作为变量的值TEST在我.bash_profile - 如果我
export TEST=hey在运行脚本之前，这是一样的 - 但是如果我删除
-l标志，则返回相同的命令TEST: hey，正如我所期望的
Can someone please explain this behaviour ? The help of bash did not... help.
有人可以解释这种行为吗？bash 的帮助没有...帮助。
回答by dg99
The -loption (according to the man page) makes "bash act as if it had been invoked as a login shell". Login shells read certain initialization files from your home directory, such as .bash_profile. Since you set the value of TESTin your .bash_profile, the value you set on the command line gets overridden when bashlaunches.
该-l选项（根据手册页）使“bash 的行为就好像它已被作为登录 shell 调用一样”。登录 shell 从您的主目录读取某些初始化文件，例如.bash_profile. 既然你设置的值TEST在你的.bash_profile，你在命令行上设置的值被重写时bash启动。
