Unix

This is one of the special UNIX type operating system devices called null device. It also could be referred as trash bit, bit bucket and other names. All data redirected to this device will be deleted instantly and you can not read from this device. It is used when you have some generated data and you do not need all of it then you redirect some streams (stdin, stderr,...) to /dev/null and forget it.

There is generally only 1 standard command for permissions on a file or directory - chmod. You can affect permissions by other commands such as changing the ownership or group ownership of a file or directory.

Other commands may be specific to different versions of Unix and Linux, so are not listed here.

You really can't. There is nothing in a prompt that would give that information.

I don't know that one could say it is "unsuitable". There are some versions of Unix that are optimized for real time activity, but in general Unix was designed as a multi-user operating system that did not have the constraints you would find in a real-time environment.

It is optimized for many users, but not necessarily for real-time event handling. Depending on the situation that the real-time calls for it might be more efficient to use an operating system or environment that was designed just for that purpose, rather than using a general multi-user system.

In Unix, setting up a real-time program would mean degrading the performance of other users, since the real-time program would need priority. Although you could do it, it really isn't in the nature of Unix to behave well this way.

In Linux and Unix-like systems, the "root" account is the only account with all possible privileges. The "root" password would be the password needed to access this account or assume its identity.

cat /etc/passwd|grep bash

It is usually pronounced v-i, by saying the two letters individually.

For Unix, any command is run as a sub-process. You don't need an actual command to create the subprocess. You can also force the process to run in the background by appending a '&' symbol at the end of the command.

Use the 'chmod' command to change permissions on any file. Note: you have to be the owner (or the superuser) to do this.

Unix itself does not use arrays. However, some shell scripting languages such as bash or ksh have simple rudimentary uses of a singly dimensioned array.

If you want anything multi-dimensional or special use such as associative arrays, then you need a scripting language such as perl, or awk or python, etc.

Vi (pronounced vee-eye), the standard screen-oriented editor provided with Unix operating systems, is the ``visual'' mode of the Ex line editor. Both Vi and Ex commands can be issued from within Vi. Source-The Internet.

zombie processes are inherited by the 'init' process (PID 1)

dollar sign ($)

first, make a file. in the file you type in the command's name. an example would be the command date. name the file what you want to call that command. when you use the command, type in cat filename and the computer will do the command.

In general, no, it is not difficult at all. As long as you stick to the POSIX (and other open standards) and use a conformant compiler for the software there shouldn't be any problem in porting software.

I do it all the time - from Linux to Unix, or Unix to Linux, makes no difference. In fact, a lot of common software is cognizant of the actual Operating System at compile time and will take care of the differences (if there are any).

You are probably referring to the fact that it is OPEN SOURCE, meaning that it is free and easily attainable. Source code is what programmers use to write programs. Open in this case means that anyone is free to examine the source code, modify the program, and even distribute their modifications, providing the license terms are followed. The terms usually include things such as keeping the GNU license intact with the distribution, and making any modified source code available under the same terms as the original program.

There are many types of text editors are present.

vi, pico, emacs, notepad, nedit, wordstar

Password aging is a tool that administrators can use to control user passwords. You can, for example, force a user to change their password every N number of days, control the intervals between password changes, etc.

Hard to answer - you don't say where the duplicated line might be.

You suspend a running (foreground) job by using the suspend keystrokes (usually ^Z).

A background job can be suspended from the background if it understands the suspend or other user kill signals. In general, however, you have to bring the background program into the foreground and then suspend it by using the action listed above.

proprietary UNIX

There is no answer to this question.

Under UNIX and Linux, commands are either shell native or external programs found on the path (which usually includes /bin /sbin /usr/bin and ~/bin)

Most UNIX and distros allow the admin to choose a shell program of choice and modify the contents of other directories and many admins allow individual users to change their personal shell and add additional executable files adding more commands.

That being the case, theoretically any command can be valid under almost any UNIX or Linux. YMMV.

1. Delete files in all mounted file systems.
2. Wipe all attached storage devices.
3. Use serial port device provided by the kernel to instruct your home-constructed coffee machine to make you one with milk and no sugar.

Click: system Preference

click accounts

click the lock( if is not open already.)

Then click the + above the lock

Then make the up the username and password you want and then click the

(allow user to administer this computer.

Restart and logging. You should be ready to use it.