Hello, i am new to unix.
I have a new dedicated server, and i am using SSH to shell to it.
it seems i have the option in my plesk control to give certain levels of shell access to a user. Can you please tell me what the following mean:

/bin/sh
/bin/bash
/sbin/nologin
/bin/ash
/bin/bsh
/bin/ksh
/usr/bin/ksh
/usr/bin/pdksh
/bin/tcsh/
/bin/csh
/bin/bash (chrooted)
/bin/rbash

thank you all in advance

Here you go:
/bin/sh, /bin/bash, /bin/ash, /bin/bsh, /bin/ksh, /bin/csh, /bin/tcsh - these are all normal shells. Will give the user the right to run any command (with their own privileges, ofcourse).

/usr/bin/ksh - this is most probably the same as /bin/ksh. On many systems, /bin is a link to /usr/bin. If that is the case, you will also find /usr/bin/sh, and so on.

/usr/bin/pdksh - this is the open source implementation of ksh. I have never used this, but I read somewhere that some features of ksh have not yet been implemented yet.

/sbin/nologin - any user that has this shell will not be able to login at the login prompt. The only way to 'become' this user is to use su. You might see this where webservers are run as user nobody. In this case, it would not be a good idea to let someone login as nobody as they will gain access to the webserver files.

/bin/bash (chrooted) - this is a version of bash that calls chroot before it runs. Again, I have never used/seen this. The chroot command basically changes the root filesystem to the path specified. The new root is then used for all file paths that start with '/'. See the man page here for more details.

/bin/rbash - this is a restricted version of bash. Here is a link to the man page of bash. You can look up the section under Restricted Shell for details on rbash.

I think that covers all the shells. Cheers.

Wow, thank you for the quick reply. Very good to know. But is there no difference between all the /bin/sh, /bin/bash, /bin/ash, /bin/bsh, /bin/ksh, /bin/csh, /bin/tcsh?

are they just giving access to a different set of commands? And if so which set has the most?

One thing i am having trouble with is editing or uploading files to most every folder beneath the webroot. that is, I seem to have access to the 'cgi-bin' folder and a folder called 'private' but almost every other folder beneath the webroot 'httpdocs' folder cant be modified by me. some cant even be read.
I have been trying to work on them through ftp and sftp. i also have a ssh shell but i dont see a way to upload anything using ssh.

any ideas how i can set permissions or modify access to these folders?
Thanks again

Look in the frequently asked questions section, there is a post comparing shells and their functionality there.

okay thanks, will check now