Basic UNIX/Linux commands
Custom commands available on departmental Linux computers but not on
Linux systems elsewhere have descriptions marked by an *asterisk.
Notice that for some standard Unix/Linux commands, friendlier versions
have been implemented; on departmental Linux computers the names of such
custom commands end with a period.
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INTERACTIVE FEATURES
TAB Command completion !!! USEFUL !!!
UPARROW Command history !!! USEFUL !!!
CTRL-C Interrupt/kill current process.
CTRL-D (at the beginning of the input line) end input.
CTRL-D CTRL-D (in the middle of the input line) end input.
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WILDCARDS AND DIRECTORIES USED IN COMMANDS
* Replaces any string of characters in a file name
except the initial dot.
? Replaces any single character in a file name
except the initial dot.
~ The home directory of the current user.
~abcde001 The home directory of the user abcde001.
.. The parent directory.
. The present directory.
/ The root directory
Example:
ls ~/files/csc221/*.txt
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REDIRECTIONS AND PIPES
COMMAND < FILE Take input from FILE instead of from the keybaord.
COMMAND > FILE Put output of COMMAND to FILE
COMMAND >> FILE Append the output of COMMAND to FILE
COMMAND 2> FILE Put error messages of COMMAND to FILE.
COMMAND 2>> FILE Append error messages of COMMAND to FILE.
COMMAND > FILE1 2> FILE2 Put output and error messages in separate files.
COMMAND >& FILE Put output and error messages in the same FILE.
COMMAND >>& FILE Append output and error messages of COMMAND to FILE.
COMMAND1 | COMMAND2 Output of COMMAND1 becomes input for COMMAND2.
COMMAND | more See the output of COMMAND page by page.
COMMAND | sort | more See the output lines of COMMAND sorted and page by page.
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ONLINE HELP
h *Custom help.
COMMAND --help | more Basic help on a Unix COMMAND (for most commands).
COMMAND -h | more Basic help on a Unix COMMAND (for some commands).
whatis COMMAND One-line information on COMMAND.
man COMMAND Display the UNIX manual page on COMMAND.
info COMMAND Info help on COMMAND.
xman Browser for Unix manual pages (under X-windows).
apropos KEYWORD | more Find man pages relevant to COMMAND.
help COMMAND Help on a bash built-in COMMAND.
perldoc Perl documentation.
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FILES AND DIRECTORIES
ls List contents of current directory.
ls -l List contents of current directory in a long form.
ls -a Same as ls but .* files are displayed as well.
ls -al Combination of ls -a and ls -l
ls DIRECTORY List contents of DIRECTORY (specified by a path).
ls SUBDIRECTORY List contents of SUBDIRECTORY.
ls FILE(S) Check whether FILE exists (or what FILES exist).
pwd Display absolute path to present working directory.
mkdir DIRECTORY Create DIRECTORY (i.e. a folder)
cd Change to your home directory.
cd .. Change to the parent directory.
cd SUBDIRECTORY Change to SUBDIRECTORY.
cd DIRECTORY Change to DIRECTORY (specified by a path).
cd - Change to the directory you were in previously.
cd. ARGUMENTS *Same as cd followed by ls
cp FILE NEWFILE Copy FILE to NEWFILE.
cp -r DIR NEWDIR Copy DIR and all its contents to NEWDIR.
cp. ARGUMENTS *Same as cp -r but preserving file attributes.
mv FILE NAME Rename FILE to new NAME.
mv DIR NAME Rename directory DIR to new NAME.
mv FILE DIR Move FILE into existing directory DIR.
swap FILE1 FILE2 *Swap contents of FILE1 and FILE2.
ln -s FILE LINK Create symbolic LINK (i.e. shortcut) to existing FILE.
quota Displays your disk quota.
quota. *Displays your disk quota and current disk usage.
rm FILE(S) Remove FILE(S).
rmdir DIRECTORY Remove empty DIRECTORY.
rm -r DIRECTORY Remove DIRECTORY and its entire contents.
rm -rf DIRECTORY Same as rm -r but without asking for confirmations.
clean *Remove non-essential files, interactively
clean -f *Remove non-essential files, without interaction.
junk FILE *Move FILE to ~/junk instead of removing it.
find. FILE(S) *Search current dir and its subdirs for FILE(S).
touch FILE Update modification date/time of FILE.
file FILE Find out the type of FILE.
gzip Compress or expand files.
zip Compress or expand files.
compress Compress or expand files.
tar Archive a directory into a file, or expand such a file.
targz DIRECTORY *Pack DIRECTORY into archive file *.tgz
untargz ARCHIVE.tgz *Unpack *.tgz archive into a directory.
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TEXT FILES
more FILE Display contents of FILE, page by page.
less FILE Display contents of FILE, page by page.
cat FILE Display a file. (For very short files.)
head FILE Display first lines of FILE.
tail FILE Display last lines of FILE.
pico FILE Edit FILE using a user-friendly editor.
nano FILE Edit FILE using a user-friendly editor.
kwrite FILE Edit FILE using a user-friendly editor under X windows.
gedit FILE Edit FILE using a user-friendly editor under X windows.
kate FILE Edit FILE using a user-friendly editor under X windows.
emacs FILE Edit FILE using a powerful editor.
vim FILE Edit FILE using a powerful editor with cryptic syntax.
aspell -c FILE Check spelling in text-file FILE.
ispell FILE *Check spelling in text-file FILE.
cat FILE1 FILE2 > NEW Append FILE1 and FILE2 creating new file NEW.
cat FILE1 >> FILE2 Append FILE1 at the end of FILE2.
sort FILE > NEWFILE Sort lines of FILE alphabetically and put them in NEWFILE.
grep STRING FILE(S) Display lines of FILE(S) which contain STRING.
grep. STRING FILE(S) *Similar to that above, but better.
wc FILE(S) Count characters, words and lines in FILE(S).
diff FILE1 FILE2 | more Show differences between two versions of a file.
filter FILE NEWFILE *Filter out strange characters from FILE.
COMMAND | cut -b 1-9,15 Remove sections from each line.
COMMAND | uniq Omit repeated lines.
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PRINTING
lpr FILE In Hawk153B or Redcay 141A, print FILE from a workstation.
lprint1 FILE *Print text-file on local printer; see help printing
lprint2 FILE *Print text-file on local printer; see help printing
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PROGRAMMING LANGUAGES
python Listener of Python 2.x programming language.
python3 *Listener of Python 3.x programming language.
idle IDE for Ptyhon 2.x.
idle3 *IDE for Ptyhon 3.x.
cc -g -Wall -o FILE FILE.c Compile C source FILE.c into executable FILE.
gcc -g -Wall -o FILE FILE.c Compile C source FILE.c into executable FILE.
c++ -g -Wall -o FIL FIL.cxx Compile C++ source FIL.cxx into executable FIL.
g++ -g -Wall -o FIL FIL.cxx Compile C++ source FIL.cxx into executable FIL.
gdb EXECUTABLE Start debugging a C/C++ program.
make FILE Compile and link C/C++ files specified in makefile
m *Same as make but directs messages to a log file.
c-work *Repeatedly edit-compile-run a C program.
javac CLASSNAME.java Compile a Java program.
java CLASSNAME Run a Java program.
javadoc CLASSNAME.java Create an html documentation file for CLASSNAME.
appletviewer CLASSNAME Run an applet.
scheme *Listener of Scheme programming language.
lisp *Listener of LISP programming language.
prolog *Listener of Prolog programming language.
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INTERNET
lynx Web browser (for text-based terminals).
firefox Web browser.
konqueror Web browser.
BROWSER Browse the Internet (with one of the browsers above.
BROWSER FILE.html Display a local html file.
BROWSER FILE.pdf Display a local pdf file.
mutt Text-based e-mail manager.
pine Text-based e-mail manager (on some systems).
ssh HOST Open interactive session on HOST using secure shell.
sftp HOST Open sftp (secure file transfer) connection to HOST.
rsync ARGUMENTS Synchronize directories on local and remote host.
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UNDER X-WINDOWS
libreoffice LibreOffice productiveity suite
soffice OpenOffice productivity suite
acroread FILE.pdf Display pdf FILE.pdf
epdfviewer FILE.pdf Display pdf FILE.pdf
okular FILE Display FILE (pdf, postscript, ...)
xterm A shell window
konsole A better shell window
xcalc A calculator
xclock A clock
xeyes They watch you work and report to the Boss :-)
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RESET
xfwm4 Reset the windows manager on Lab and MiniLab computers.
Ctrl-Alt-Backspace Restart the X-server. (You may need to do that twice.)
clear Clear shell window.
xrefresh Refresh X-windows.
reset *Reset session.
setup-account *Set up or reset your account (Dr. Plaza's customizations)
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MISCELLANEOUS
exit Exit from any shell.
logout Exit from the login shell and terminate session.
svn Version control system.
date Display date and time.
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COURSEWORK IN DR. PLAZA'S COURSES
Commands and directory names related to csc219 have 219 as a suffix.
By changing the suffix you will obtain commands for other courses.
ls $csc319 *List files related to csc319.
cd $csc319 *change into instructor's public directory for csc319.
cp $csc319/FILE . *Copy FILE related to csc319 to the current directory
cp -r $csc319/SUBDIR . *Copy SUBDIR of csc319 to the current directory.
submit *Submit a directory with files for an assignment.
grades *See your grades. Used in some courses only.
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PROCESS CONTROL
Notes: A process is a run of a program;
One program can be used to create many concurrent processes.
A job may consist of several processes with pipes and redirections.
Processes are managed by the kernel.
Jobs are managed by the shell.
CTRL-Z Suspend current foreground process.
fg Bring job suspended by CTRL-Z to the foreground.
bg JOB Restart suspended JOb in the background.
ps List processes.
ps. *List processes.
jobs List current jobs (A job may involve many processes).
kill PROCESS Kill PROCESS (however some processes may resist).
ctrl-C Kill the foreground process (but it may resist).
kill -9 PROCESS Kill PROCESS (no process can resist.)
kill. PROCESS *Kill PROCESS; same as kill -9.
COMMAND & Run COMMAND in the background.
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ENVIRONMENT VARIABLES IN BASH
env | sort | more List all the environment variables with values.
echo $VARIABLE List the value of VARIABLE.
unset VARIABLE Remove VARIABLE.
export VARIABLE=VALUE Create environment variable VARIABLE and set to VALUE.
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