4.7 Invoking the Shell

The command interpreter for the Bourne shell (sh ) or the Korn shell (ksh ) can be invoked as follows:

sh   [options
]  [arguments
]

ksh  [options
]  [arguments
]

ksh and sh can execute commands from a terminal, from a file (when the first argument is an executable script), or from standard input (if no arguments remain or if -s is specified). ksh and sh automatically print prompts if standard input is a terminal, or if -i is given on the command line.

Arguments

Arguments are assigned in order to the positional parameters $1 , $2 , etc. If array assignment is in effect (-A or +A ), arguments are assigned as array elements. If the first argument is an executable script, commands are read from it, and the remaining arguments are assigned to $1 , $2 , etc.

Options

-c str

Read commands from string str .

-D

Print all $"..." strings in the program. ksh93 only.

-i

Create an interactive shell (prompt for input).

-I file

Create a cross-reference database for variable and command definitions and references. May not be compiled in. ksh93 only.

-p

Start up as a privileged user (Bourne shell: don't set the effective user and group IDs to those of the real user and group IDs. Korn shell: don't process $HOME/.profile ).

-r

Create a restricted shell (same as rksh or rsh ).

-s

Read commands from standard input; output from built-in commands goes to file descriptor 1; all other shell output goes to file descriptor 2.

The remaining options to sh and ksh are listed under the set built-in command.