Basic Unix Commands

NOTE: All commands must be in lowercase unless specified otherwise.

Click on the command for a more detailed explaination.

cd dir_opt

The cd command is used the change directory, that is, it sets the current working directory of the current shell to be the directory specified after the cd. If no directory is specified, then the user's shell sets itself back to that user's home directory. If directory specifies a complete path starting with /, ., .., directory becomes the new working directory. If neither case applies, cd tries to find the designated directory relative to one of the paths specified by the $CDPATH shell variable. $CDPATH has the same syntax as, and similar semantics to, the $PATH shell variable. cd must have execute (search) permission in directory.

cp old new

The cp command is used to copy a file to a new location, or to copy many files into a target directory. Directory hierarchies can also be copied using the option -r.

To copy a file named image.jpg to the directory /vol/abyss/tmp with the new name of bleeding-heart.jpg the following command could be used:

cp image.jpg /vol/abyss/tmp/bleeding-heart.jpg

cp foo bar qux /vol/abyss/tmp

df -lk dir_opt

The df displays the amount of disk free on the filesystem containing each argument pathname. If no pathnames are given, the space available on all currently mounted filesystems is shown. The -k, --kilobytes switch prints sizes in 1K blocks instead of 512-byte blocks.

gdir dirlist

Creates new directories with group-write and sticky, suitable for sharing within a group. Use "ls -l" to see group name. May be run on existing directories as well to similar effect.

grosview

grosview is a good way to get an idea what resources are being used on you machine in graphical format grosview is a program that calls gr_osview with a bunch of parameters set so you don't have to worry about them. here is a description of gr_osview itself: This command provides a graphical display of usage of certain types of system resources. This display provides a real-time window into the overall operation of the system. The main display element is a rectangular area which is filled by uniquely colored bands, each band signifying a sampled variable measuring system performance. This rectangular area is called a bar throughout the rest of this description.

hinv

hinv displays the contents of the system hardware inventory table. This table is created each time the system is booted and contains entries describing various pieces of hardware in the system. The items in the table include main memory size, cache sizes, floating point unit, and disk drives. Without arguments, the hinv command will display a one line description of each entry in the table.

ls -FCasH
ls -FlasH

The ls command is used to list files in a directory, defaulting to the current directory. It is similar to the DOS command dir. There are many options available with ls, but the most commom have been prepacked at this site as l (that's just the letter "L" in lower case) for a short listing, and ll (that's two lowercase "L"s) for a long listing with file permissions, user and group ownerships, and last time of modification.

A specific list of files and/or directories may be given after the ls command or after one of its prepacked forms. A single dot can be used to refer to the current directory.

mkdir dirlist

The mkdir command is used to make directories. The specified directories are created, and are initially empty, meaning they only have entries . (dot) and .. (dotdot), which are names for the current and parent directories, respectively.

mv old new
mv files dir

The mv command is used to move file and/or directories to new locations. This includes simply moving a file to a new name within the current directory. This is very similar to the cp command except for several things:

1. The files will only be available via the new names/locations.
2. mv is usually much faster than cp.
3. They're spelled differently. :-)

osview

osview monitors various portions of the activity of the operating system and displays them using the full screen capabilities of the current terminal.

please request

	where request is one of the following single words,
	from the implemented functions marked with '*':
		* help      - output help about this program
		* allowed   - tell you if you may issue requests
		* reboot    - reboot this host
		* shutdown  - shutdown this host
		* halt      - shutdown this host
		* gamma     - modify the gamma level
		* automount - restart the automounter
		  renice    - make a process defer to others
		  kill      - kill a process
		  suspend   - suspend a process temporarily
		* tidydisk  - free up likely disk space
		* tablet    - configure a tablet for Alias
	Example: please help
	The executing user must have permission for the requested action.
	Most actions are automatically logged in the system logs.

ps -f -u user

       ps prints certain information about active processes.  Without options,
       information is printed about processes associated with the controlling
       terminal.
 
       here are a few helpfull command lines to use for ps:
           
	 ps -u user                 gives a short listing of user processes
	 ps -f -u user              gives a long listing of user processes
     	 ps -ef | grep processname  gives a listing of every instance of processname
			    	   

rlogin hostname

The rlogin is used to login to remote machines within a given domain or within a given site. The hostname to which to connect is specified after the rlogin command.

rm files

The rm command is used to remove files. Simply give the filenames to remove after the rm. Files thus removed are GONE FOREVER. The packaged version of rm here is nicer, and asks you, once, if you're sure you want to remove the files. However, if you say yes, they're still GONE FOREVER...

rmdir dirlist

The rmdir command is used to remove directories. The directories to remove must be empty at the time.

rlogin hostname cmd

Rsh connects to the specified hostname, and executes the specified cmd. Rsh copies its standard input to the remote command, the standard output of the remote command to its standard output, and the standard error of the remote command to its standard error.

top

This command displays a sorted list of processes which are using some portion of the available CPU cycles on a machine. The display is updated every interval. The following fields are displayed in order for each process: user name, process ID, process group ID, CPU usage, processor currently executing the process ( if process not currently running), process priority, process size (in pages), resident set size (in pages), amount of CPU time used by the process, and the process name.