Created On: 7/23/2004 8:54:00 AM ls
dir
List the contents of the current directory. The command dir is an alias to ls so these two commands do exactly the same thing. The file listing is normally color-coded: dark blue= directories, light grey = regular files, green = executable files, magenta = graphics files, red = compressed (zipped) files, light blue = symbolic links, yellow = device files, brown = FIFO ("First-In First-Out" named pipes).
ls -al |more
List the content of the current directory, all files (also those starting with a dot), and in a long form. Pipe the output through the "more" command, so that the display pauses after each screenful. The ls command has several very useful options. Some of these may have shortcuts (aliases) to avoid clumsy typing. Try ll (="long ls", an alias to ls -l). Another option I use quite often is ls -ad (list all the subdirectories in my current directory, but don't list their contents).
cd directory
Change directory. Using "cd" without the directory name will take you to your home directory. "cd - " will take you to your previous directory and is a convenient way to toggle between two directories. "cd .." will take me one directory up (very useful).
./program_name
Run an executable in the current directory. The ./ is needed when the executable is not on my PATH. An executable which is on my PATH is simply run using: program_name
shutdown -h now
(as root) Shut down the system to a halt.
vlock
(Not present on older versions of RedHat.) Lock a local (text mode) terminal. I can also use vlock -a to lock all terminals (probably not a good idea). The best is probably to log out. You don't use vlock in GUI--the windows managers come with password-protected screensaver and a locking utility (the small icon with padlock in KDE, the keyboard shortcut ).
Switch to the first text terminals. Under Linux you can have several (6 in standard setup) terminals opened at the same time. This is a keyboard shortcut, which means: "press the control key and the alt key, hold them. Now press . Release all keys."
(n=1..6)
Switch to the nth text terminal. (The same could be accomplished with the rarely used command chvt n. "chvt" stands for "change virtual terminal"). In text terminal (outside X), you can also use (the key is not needed).
tty
Print the name of the terminal in which you are typing this command. If you prefer the number of the active terminal (instead of its name), it can be printed using the command fgconsole (="foreground console").
Switch to the first GUI terminal (if X-windows is running on the 7th terminal, where it typcially is).
(n=7..12)
Switch to the nth GUI terminal (if a GUI terminal is running on screen n-1). On default, the first X server is running on terminal 7. On default, nothing is running on terminals 8 to 12--you can start subsequent X server there.
(In a text or X terminal) Autocomplete the command if there is only one option, or else show all the available options. On newer systems you may need to press . THIS SHORTCUT IS GREAT, it can truely save you lots of time.
(In a text or X terminal) Scroll and edit the command history. Press to execute a historical command (to save on typing). scrolls back.
Scroll terminal output up. This works also at the login prompt, so you can scroll through your bootup messages. The amount/usage of your video memory determines how far back you can scroll the display. scrolls the terminal output down.
<+>
(in X-windows) Change to the next X-server resolution (if you set up the X-server to more than one resolution). For multiple resolutions on my standard SVGA card/monitor, I have the following line in the file /etc/X11/XF86Config (the first resolution starts on default, the largest resolution determines the size of the "virtual screen"):
Modes "1024x768" "800x600" "640x480" "512x384" "480x300" "400x300" "1152x864"Z
Of course, first I had to configure the X server, either by using Xconfigurator, xf86config, or manually by edition the file /etc/X11/XF86Config, so that it supports the above resolutions (mostly the matter of uncommenting the line that defines my video chipset, and specifying the synchronization frequencies my monitor supports). XFdrake (Mandrake configuration utility) can do it from GUI. See also the commands xvidtune and xvidgen.
<->
(in X-windows) Change to the previous X-server resolution.
(in X-windows, KDE) Kill the window I am going to click with my mouse pointer (the pointer changes to something like a death symbol). Similar result can be obtained with the command xkill (typed in X-terminal). Useful when an X-window program does not want to close (hangs?).
(in X-windows) Kill the current X-windows server. Use if the X-windows server cannot be exited normally.
c
Kill the current process (works mostly with small text-mode applications).
d
(pressed at the beginning of an empty line) Log out from the current terminal. See also the next command.
d
Send [End-of-File] to the current process. Don't press it twice else you also log out (see the previous command).
s
Stop the transfer to the terminal.
q
Resume the transfer to the terminal. Try if your terminal mysteriously stops responding. See the previous command.
z
Send the current process to the background.
exit
Logout. I can also use logout for the same effect. (If you have started a second shell, e.g., using bash, this command will make you exit the second shell, and you will be back in the first shell, not logged out. Then use another exit to logout.)
reset
Restore a screwed-up terminal (a terminal showing funny characters) to default setting. Use if you tried to "cat" a binary file. You may not be able to see the command as you type it, but it still will work.
Paste the text which is currently highlighted somewhere else. This is the normal "copy-paste" operation in Linux. It a fast and powerful supplement to the widely-known GUI "copy-paste" menu-based operation. (It doesn't work inside older versions of Netscape which use the Mac/MS Windows-style "copy-paste" exclusively. It does work in the text terminal if you enabled "gpm" service using "setup". It also works inside any dialog boxes, etc.--really convenient!) It is best used with a Linux-ready 3-button mouse (Logitech or similar) or else set "3-mouse button emulation". The is normally emulated on a 2-button mouse by pressing both mouse buttons simultanously.
~
(tilde character) My home directory (normally the directory /home/my_login_name). For example, the command cd ~/my_dir will change my working directory to the subdirectory "my_dir" under my home directory. Typing just "cd" alone is an equivalent of the command "cd ~". I keep all my files in my home directory.
.
(dot) Current directory. For example, ./my_program will attempt to execute the file "my_program" located in your current working directory.
..
(two dots) Directory parent to the current one. For example, the command cd .. will change my current working directory one one level up.
Some additional KDE keyboard shortcuts (useful, but non-essential)
Walk through windows. To walk backwards:
Walk through desktops. To walks backwards:
Show the table of processes running on my system. Allow me to kill any of the processes I started (or send other signals to them).
Access the K-menu ("Equivalent to MS Windows "Start" menu).
Emulate the mouse using the arrow keys on the keyboard.
Drag a window to move it. Normally, I move a window by dragging its top title bar, but occassionally I manage to get it off the screen. With this shortcut, I can drag by any part of the window.
Take a snapshot of the current window into the clipboard.
Take a snapshot of the entire desktop into the clipboard.
Lock the desktop.
Toggle hide/show the desktop (great to hide the Solitaire game when your boss walks in).
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