About Shell Scripts

Shell scripts, also called batch jobs, are a sequence of command-line instructions that are assembled in a file. Script files are made executable by the chmod command. If scripts are invoked, a command interpreter is started. Each instruction is interpreted as if the instruction were typed manually by the user who is running the script. csh, tcsh, sh, or ksh are typical command interpreters. You can invoke arbitrary commands, applications, and other shell scripts from within a shell script.

The command interpreter can be invoked as login shell. To do so, the name of the command interpreter must be contained in the login_shells list of the grid engine system configuration that is in effect for the particular host and queue that is running the job.

The grid engine system configuration might be different for the various hosts and queues configured in your cluster. You can display the effective configurations with the -sconf and -sq options of the qconf command. For detailed information, see the qconf(1) man page.

If the command interpreter is invoked as login shell, the environment of your job is the same as if you logged in and ran the script. In using csh, for example, .login and .cshrc are executed in addition to the system default startup resource files, such as /etc/login, whereas only .cshrc is executed if csh is not invoked as login-shell. For a description of the difference between being invoked and not being invoked as login-shell, see the man page of your command interpreter.