In the TCSH (Tenex C Shell) and CSH (C Shell) shells, you can set the PATH variable to specify the directories that the shell should search for executables.
To set the PATH variable in TCSH or CSH, you can use the setenv built-in command. For example, to set the PATH variable to include the /usr/local/bin and /usr/local/sbin directories, you can use the following command:
setenv PATH /usr/local/bin:/usr/local/sbin:$PATH
This will add the /usr/local/bin and /usr/local/sbin directories to the beginning of the PATH, and preserve the directories that were already in the PATH.
You can also use the set path built-in command to set the PATH variable in CSH. For example:
set path = (/usr/local/bin /usr/local/sbin $path)
This will have the same effect as the setenv command in TCSH.
It is important to note that the PATH variable is case-sensitive in TCSH and CSH, and should always be written in uppercase.
For more information about the setenv and set path commands and their options, you can consult the documentation for your specific Unix or Linux system.