hi guru,
When I take a look in my userlist, found that some of the user granted "bash" where some is granted "ksh".

* Bash shell
netdump, pvm, cyrus, mysql,postgres, amanda, user, ftpuser

What are those accounts used for?

ksh is assigned to those users created by me.

any ideas?
Nick

mysql is propably the user administring mysql. ftpuser is probably the default user when you connect to your server via ftp. postgres is probably administring postgreSQL. amada is probably doing backups. netdump is probably allowed to access low level network APIs. pvm probably has the right to administer pvm. Cyrus is probably running the IMAP server and user is probably the first user that was installed by the installer?

Thanks for you info,
Just wondering why bash is given to those accounts where ksh is given to the user account created by myself.
Is it the linux default?

Bash is the GNU shell. Most GNU systems use bash by default. Over 99.999% of linux systems are acually GNU systems.
Moreover, this is probably a personnal opinion, but I find bash vastly superior to ksh. May I ask you what you prefer in ksh? Is it to stay compatible with AIX or something?

EDIT: I re-read your question. I didn't get it at first. You mean 'linux' is choosing ksh for you? What is the distro and how do create the users? There must be a configuration somewhere to create the users. If you are using useradd, check /etc/default/useradd. ksh is not the GNU default. It's probably your distro which is weird or somebody did change the default configuration.

This server has been set up by an ex-colleague, the default for /useradd is bash.
Don't know why my colleague is using ksh for some of the user accounts those have been used by users running a macro program to FTP Excel from local PC to Linux server for importing data.
Maybe compatible with Windows, right?

Is there any reason to use KSH over Bash? Security issue?
If we change the KSH back to Bash, is there any concern?
sorry i'm just a newbie for unix
thanks again

The usage is somewhat different. Some users are more confortable with ksh, maybe because they've spent too much time on AIX or something. Personally, ksh gives me headaches. It has nothing to do with security. It's just about habits. bash is like a shortcut. Some people will insist on taking the long path because it's the path they know and they are afraid to be lost if they take another path. It's better you ask the users if they prefer to use ksh.
Anyway, it's not that important. It's just the default shells for the users. It's very easy for the user to use ksh or bash as they like despite their default shell. If they prefer bash, they just have to type 'bash' or put that in their .profile and that's all

ksh is very similar to bash (ie most cmds in a script will work unchanged if transferred). ksh tends to be the (modern) default on commercial Unices.
Then of course you've got csh (old) tsch (updated to csh) and zsh...
The main thing in production envs is to specify at the top of the script which shell it expects, just in case the default for that acct is not the same as the one it was written under.