47

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?

  • 1
    Not really a programming question. In the future, you'd probably best ask questions like this on [Unix/Linux](http://unix.stackexchange.com/). – tylerl Feb 05 '13 at 05:06

6 Answers6

57

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
jordanm
  • 773
  • 5
  • 9
  • 2
    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? –  Feb 05 '13 at 05:34
  • 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 05 '13 at 05:42
9

For the case where you're trying to use a shared account (for whatever reason) and can't change the default shell, then you can run 

ssh -t <user@hostname> bash -l

If you need to keep your environment from some other shell, then you can run that shell first; for example

ssh -t <user@hostname> ksh -c bash -l
UKMonkey
  • 191
  • 1
  • 3
7

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.

Dirk Eddelbuettel
  • 1,241
  • 6
  • 9
  • 1
    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 05 '13 at 05:03
  • 4
    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 05 '13 at 05:04
  • 1
    Nonsense. Running Linux since '94 here. Never busted `/etc/passwd`. – Dirk Eddelbuettel Feb 05 '13 at 05:04
  • 2
    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 05 '13 at 05:06
  • 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 05 '13 at 05:08
  • See "posix mode" in the bash manpage. When used in scripting as `/bin/sh`, it's not really a problem (which is what I believe you are referring to). In interactive use, differences are more likely to be noticed. E.g. When executed as `/bin/sh` not all RC files are sourced. – jordanm Feb 05 '13 at 05:14
  • on jailbroken ios this is the only way. – Wyatt Ward Mar 24 '15 at 23:55
4

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
tylerl
  • 2,155
  • 1
  • 15
  • 21
1

Neither chsh or usermod were working for me, but I found that you can do this through PuTTY.

Go to Connection > SSH and set the Remote command to bash.

Note that you won't be able to exit to your default shell, it will just close the connection.

Chris
  • 131
  • 8
1

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.

mvp
  • 4,320
  • 21
  • 27
  • 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 05 '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 05 '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 05 '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 05 '13 at 21:09