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I dont know why, I wrote a script yesterday about select directory, then I find no matter what option I gave, I just wouldn't change directory.
So I wrote a script today which contains only one line.
Code:
cd /home
and I just failed, with no error message. Any ideas?
Additional, I'm not at /home
It's about scope. when you run the script it invokes a new shell, and it's within that shell instances that you change directory. When you finish the script, that shell terminates, so nothing inside the shell persists to the parent it was executed from. If you want to run a list of commands in your current shell, you'd source the file. run ". myscript" and you'll change directory. the source dot there is broadly like an "include" statement in programming languages.
It's about scope. when you run the script it invokes a new shell, and it's within that shell instances that you change directory. When you finish the script, that shell terminates, so nothing inside the shell persists to the parent it was executed from. If you want to run a list of commands in your current shell, you'd source the file. run ". myscript" and you'll change directory. the source dot there is broadly like an "include" statement in programming languages.
Then I find in a sub shell, pwd is still there, so Where can,I get to know the difference between bash and a sub shell.
I simply treat /bin/bash as a shell? Am I right?
Now I have some questions list here.
1:I invoke a sub ahell, where does this sub shell come from?
2:It's said that env variables is still supported in sub shell, why doesn't it have complete builtin command?
Thanks for your help.
Then I find in a sub shell, pwd is still there, so Where can,I get to know the difference between bash and a sub shell.
I simply treat /bin/bash as a shell? Am I right?
Bash is a shell (BASH -> Bourne Again SHell). The term bash shell is a pleonasm.
Quote:
Originally Posted by xeechou
1:I invoke a sub ahell, where does this sub shell come from?
From the mother shell (the initial shell started when logging in). A mothewr shell can spawn child shells, which in turn can spawn child shells.
Quote:
Originally Posted by xeechou
2:It's said that env variables is still supported in sub shell, why doesn't it have complete builtin command?
Thanks for your help.
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