I was surprised that I didn't find this question already on the site. So, today $ came up after I logged in as a new user. This was unexpected because my main user's prompt starts with username@computername:~$.
So, how do I switch from this other shell to bash?
Assuming the unknown shell supports running an absolute command, you could try: /bin/bash
To change the default shell, I would use chsh(1). Sample usage: chsh -s /bin/bash $USER
/etc/passwd chsh(1) will only allow to change to a shell that is listed in /etc/shells (and is available, presumably). chsh -l lists the alternatives. Be careful, some (like nologin) are defined for accounts that should never be used to login (nice way to lock yourself out), there might be local additions for special uses. You type in bash. If you want this to be a permanent change the default shell to /bin/bash by editing /etc/passwd.
Here's some snippets from my /etc/passwd:
avahi:x:84:84:Avahi daemon:/:/bin/false xenoterracide:x:1000:100::/home/xenoterracide:/bin/zsh postgres:x:88:88::/var/lib/postgres:/bin/zsh bob:x:1001:1001::/home/bob:/bin/bash usbmux:x:140:140:usbmux user:/:/sbin/nologin The very last field contains the shell, Modifying the field after the last : to a valid or invalid shell will work. /bin/false and /sbin/nologin both mean the user doesn't have a real login shell, although if pam is not set up right this doesn't mean they can't login (I reported a bug on this in Arch Linux, because you can login graphically without having a login shell). /bin/bash and /bin/zsh are both valid shells, see /etc/shells for a list of valid shells on your systems. Here's my /etc/shells if you're interested.
/bin/sh /bin/bash /bin/ksh /bin/zsh /bin/dash Yes you can use chsh or usermod to do the same things, please remember these are just structured text files, and TIMTOWTDI.
chsh instead of manually editing passwd /etc/passwd I didn't feel like listing any of them, because I always do it manually. chsh and usermod can both do it. If chsh or manually editing the config won't work, but a ~/.profile script is executed at login, add this line:
exec /bin/bash --login 
touch ~/.bash_profile or otherwise bash will exec itself in a loop: bash takes ~/.profile in case ~/.bash_profile doesn't exist.
$came up rather thanusername@computername:~$doesn't mean it wasn't bash. The exact formatting of the prompt is set by the PS1 variable, which can be set up or customized differently for different users.echo $SHELLto find out what your current shell is./bin/shoften doesn't mean much that's usually a symlink to something else. I'd typels -l /bin/shto see what it's a symlink to. In some cases being a symlink to something changes its behavior, I don't think bash is that way.bashas/bin/shdisables many bash features (it goes into POSIX compliance mode).