At my /etc/passwd file user1 using /bin/bash as a default login shell.
user1:x:602:603::/home/user1:/bin/bash

so once i login user1, i am using bash shell. ok how to temporary change my current shell bash to korn or other shell.

$tcsh
this command to temporary change current bash shell TC shell.

$chsh
this command to permanant change login shell.

problem:
1. command tcsh ,i am in RHEL5 than can be use, but other linux os may cannot been use, or sunOS also cannot use.

2. Any other common command to suitable for all linx or UNIX OS to temporary change shell and permanant change shell?


Thank.

You can, simply, change shells by executing the shell program; e.g., if you're login shell is BASH, you can change to C-shell by typing chs or Korn shell by typing ksh.

Now, here's the rub: doing that does not load the content of .login (in the case of C-shell) or .profile (and, possibly, .kshrc) in the case of Korn shell. It's possible that both C-shell and Korn shell will inherit any environment variables set by the initial BASH login but I wouldn't want to count on that in every situation. If you only need to temporarily change shells to run, say, a shell program, it would be much better (and more reliable) to embed #!/bin/shelname as the first line of your shell program; e.g., #!/bin/chs, #!/bin/ksh, etc. and set any special environment variables in the shell program.