When you have successfully accessed the POSIX subsystem, the POSIX shell is started.
If you are using the POSIX shell in interactive mode, the POSIX shell outputs the value of the environment variable PS1 as a prompt before reading a command. By default, this is the dollar sign ($), or (#) for the privileged user, followed by a blank (' ').
Commands are entered in the following format:
command[ options][ parameters] ...
For command you must specify the name of the POSIX command or shell procedure which is to be executed. The options allow you to specify control instructions for command execution. Under parameters you can enter a call argument which the POSIX shell passes to the command. You may also enter multiple call arguments for certain commands.
At character-mode terminals you must use tabs or spaces to separate the command names and call arguments. After the final call argument you can conclude command input by pressing the Enter key (at character-mode terminals) or EM DUE (at block-mode terminals).
Pure BS2000 programs cannot be started from within the POSIX shell.
If the screen line is too short for the required input you may proceed in one of two ways:
At the end of the line you may simply continue to type without pressing the Enter key. When you have entered the complete command, press the Enter key to terminate input.
- Enter \ (backslash) and press Enter to continue the line. The backslash (\) prevents the Enter key from terminating command input. You may then continue to enter the command. When you press Enter (without \), the command is executed.
Every POSIX command returns a value to the POSIX shell in which it was called. This is its exit status. If the command was executed correctly this value is 0; if errors were encountered its value is not equal to 0.
If a command outputs information on screen and the output exceeds the capacity of a screen page, then at character-mode terminals you can pause the output by pressing the key combination CTRL+S and continue it by pressing CTRL+Q. This function is not supported at block-mode terminals.