Download Troubleshooting

Utilities
© 2008, QNX Software Systems GmbH & Co. KG.
You can combine multiple options that don’t take an argument. The -ceisu notation
is shorthand for -c -e -i -s -u.
If an argument to a command starts with a hyphen, you can signal the end of the
options by using a double hyphen:
ls -l -- -my_file
For more information, see Utility Conventions in the Utilities Reference.
Displaying online usage messages
If you want a detailed description of a utility, see the Utilities Reference. But if you
just want a quick reminder of the syntax and options, you can display the utility’s
online usage message by invoking the use command (it’s similar to man in UNIX and
Linux). For example, to display the message for more, type:
use more
If you request usage for a command, and the command either doesn’t have an
executable in the current path or doesn’t contain usage message records, use displays
an error message. For more information, see use in the Utilities Reference — or
simply type use use.
Executing commands on another node or tty
If the machines on your network are running Qnet (see Using Qnet for Transparent
Distributed Processing), you can execute commands on another machine. This is
known as remote execution. For example:
on -n /net/dasher date
where /net/dasher is the name of the node that you want to run the command on.
When you invoke a command on another node, the command’s standard input,
standard output, and standard error output are displayed on your console screen (or
terminal) unless you explicitly redirect them to another device.
To run a command on a specific tty, use the -t option, specifying the terminal name.
For example:
on -t con3 login root
For more information, see the on command in the Utilities Reference.
Priorities
By default, when you start a utility or other program, it runs at the same priority as its
parent. (Actually, priorities aren’t associated with a process, but with the process’s
threads.) You can determine the priority of a process’s threads by looking at the output
of the pidin (Process ID INformation) command.
If you want to run something at a specific priority, use on, specifying the -p option. If
you want to specify a relative priority, use the nice command.
September 30, 2008
Chapter 4 • Using the Command Line
45