UMBC CMSC 104
Simple UNIX Commands
Lists the files in the current directory.
ls -l gives more
information about the files. -l stands for the "long" version.
Copies a file.
cp sample.c example.c makes a copy of sample.c
and names the new copy example.c.
sample.c still exists.
Renames a file.
mv average.c mean.c changes the name of the file
from average.c to mean.c.
average.c no longer exists.
Removes or deletes a file.
rm olddata.dat would delete the file
Types the contents of a file onto the screen one page at a
more example.txt would show the contents of the file
example.txt one screenfull at a time.
You must press the spacebar to
advance to the next page. You may type q to quit or b to go back to the
beginning of the file.
Displays the contents of a file onto the screen all at once. If the file
is too long to fit onto the screen, it scrolls. cat is also used to
combine two or more files.
cat mean.h just displays the contents of
cat mean.h counts.h statistics.h concatenates the two files
mean.h and counts.h by tacking the contents of counts.h onto the end of mean.h
and calls the new, combined file statistics.h
mean.h and counts.h still
exists in their original form.
Makes a new subdirectory in the current directory.
will make a new directory called 104 in the current directory.
Removes a subdirectory from the current directory, but the subdirectory
must contain no files. You must delete all of the files from a directory
before you are allowed to delete it.
passwd is used to change your password. After typing passwd, you
will be prompted to enter your old password. Then you will be prompted to
enter your new password. After entering the new password, you will be asked to
enter the new password again. If the two versions of the new password match
(you didn't make a typo either time), your password has been changed. NOTE:
There is a system in place on the UMBC machines that will not allow you to use
passwords that are too common and easy to guess. You may find that the system
will not allow you to use your first choice in passwords. Choose a different,
The command cd alone will return you to your home directory.
followed by a directory name the is found in the current directory, as
cd 201, will change from the current directory to its
subdirectory called 201, if that subdirectory exists.
cd ~jdoe1 will
change to the home directory of the user named jdoe1
Moves you up one level in the directory tree.
Tells you the directory you are currently in
Prints a file
lpr -Pacsps sample.txt would print the file called sample.txt on the
Academic Computing Services postscript printers found in Room ECS 019. There
is a charge per page for printing.
Gives a description of a UNIX command and also C keywords and functions.
So man cat will tell you all about the cat command. If you don't know
the name of a command, but you do know what you want to do, use man -k.
If you've forgotten the command for copy, you could type in man -k copy
and you would be supplied with the name of the command (in this case cp) and a
description of how the command works.
The finger command lets you get information about a user. If you know
their login name, finger jdoe1@gl will tell you if that person is
logged on, what programs they are running and how long they've been idle. If
they're not logged on, it will tell you when they were last logged on and
whether they have any unread mail. If you want to find a person's email
address, use finger like this: finger fkuss1 In this case, the finger
command will give you the addresse, email@example.com If the person has a
common name, you will get everyone with that name.
Tells you the login names of all of the people that are currently logged
onto the same computer as you are. They are not in any order and it will
scroll off the screen.
"The pipe" is used to combine commands. It "pipes" the output of one
command to be used as input to the next command. Here's a typical use of the
pipe. who|sort|more This will give you all of the people's login names
that are currently logged onto the same machine as you, in sorted order, one
page at a time.
This command can be used to exchange short messages back and forth with
someone else who is logged on. You get a split screen. You type within the top
half and the other person's typing shows up in the bottom half. Great for
getting in touch with someone in one of the labs, or even someone who is
logged on from home. It is quite slow and bothersome. Example: talk
Last Modified: Wednesday, 24-Jan-2001 10:56:54 EST