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I have a hosted Debian server. When I log in via ssh, I'm greeted with a sh environment. How do I change it so I start in a bash environment?

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migrated from stackoverflow.com Feb 5 '13 at 6:40

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Not really a programming question. In the future, you'd probably best ask questions like this on Unix/Linux. –  tylerl Feb 5 '13 at 5:06
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4 Answers 4

up vote 5 down vote accepted

As a regular user, you can change your default login shell using the chsh command. Here is an example:

chsh -s /bin/bash

Another option is to use usermod as root:

usermod -s /bin/bash username
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usermod worked like a charm. Is there some way to set it to default to bash when I add a new user, or do I have to run the command each time? –  bbbgscott Feb 5 '13 at 5:34
    
If you use adduser, it should set it to bash by default. The default is configured in /etc/adduser.conf. Otherwise specify the shell explicitly with useradd. –  jordanm Feb 5 '13 at 5:42
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Default system shell /bin/sh in recent Ubuntu releases is configured to be /bin/dash. By simply running following command:

sudo dpkg-reconfigure dash

you can change it back to old default of /bin/bash.

With this, you can achieve desired effect of having bash as interactive shell without changing any user settings (no chsh or usermod), and it will work for all users who currently have shell set to /bin/sh.

There is only one small downside to this: Ubuntu boot time might slightly increase, because dash takes less memory to load and slightly faster to run (no wonder - it is so limited in features). But I think it will be rather difficult to measure this effect, especially for hosting environment.

Also, it is sometimes annoying to see shell scripts that fail to work properly because they use some bash advanced features which are not supported by dash. Using this recipe will make sure this will not happen.

For more information, see Ubuntu wiki about this issue.

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you should keep the use cases apart: /bin/sh is used as the interpreter for POSIX compatible shell scripts - it's not necessarily the best interactive shell; if you want bash to be your system shell, you should set your preferred login shell using chsh or proper adduser calls. using dpkg-reconfigure is a bad choice if userA wants zsh and userB wants bash and both insist in having /bin/sh as their default shell. –  umläute Feb 5 '13 at 12:49
    
if userA is explicitly configured to zsh, and userB to bash they will have it. If userC configured to sh, he will have bash, which is current Ubuntu default for new users anyway –  mvp Feb 5 '13 at 17:41
    
sure, but your solution suggested something like dpkg-reconfigure zsh to set zsh as /bin/sh, and then dpkg-reconfigure dash to set dash as /bin/sh which is kind of a deadlock; i'm mainly saying that it is preferrably to set the login shell to the shell one wants to use rather than going through hoops to make /bin/sh a good login shell. –  umläute Feb 5 '13 at 19:46
    
I only said that dpkg-reconfigure dash can make sh point to bash, rather than crippled dash. All other shells will be still intact. –  mvp Feb 5 '13 at 21:09
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You need to edit your user profile, you can do this directly by editing the /etc/passwd file, or you can use the usermod command to do it for you. The syntax you're looking for looks something like this:

usermod -s /bin/bash joeuser
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You edit /etc/passwd where the last entry is the default shell. Make it /bin/bash.

Alternatively, you could alter alter the system default of /bin/sh not being bash.

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Yo, what's up with the drive-by downvote? Eg Ubuntu does default to /bin/sh being /bin/dash. And for what it is worth the other two answers are identical and achive the same end by different means. Whatever. –  Dirk Eddelbuettel Feb 5 '13 at 5:03
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Manual edits of /etc/passwd are highly discouraged. An editing mistake can break logins for all users, requiring recovery media or a boot to single user mode to repair. There are tools such as usermod for changing /etc/passwd. –  jordanm Feb 5 '13 at 5:04
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Nonsense. Running Linux since '94 here. Never busted /etc/passwd. –  Dirk Eddelbuettel Feb 5 '13 at 5:04
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Good to hear you have been very careful. Not everyone has. Another note on your update, launching /bin/bash as /bin/sh is the same as executing it with --posix, which may have undesirable results. –  jordanm Feb 5 '13 at 5:06
    
Look, I've been a Debian developer/maintainer since 1995 too. We used to have bash as a default, we switched to simpler shells for a variety of reason. I have been using /bin/bash as my shell all those years on all machines. You need a more concrete argument. –  Dirk Eddelbuettel Feb 5 '13 at 5:08
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