that is accessed with the shell in UNIX.
Here is some basic commands:
cal
This command will print a calendar for a specified month and/or year.
To show this month's calendar, enter:
cal To show a twelve-month calendar for 2004, enter:
cal 2004
To show a calendar for just the month of June, 1970, enter:
cal 6 1970
For more detailed information, see the Knowledge Base document In Unix, how can I display a calendar?
cat
This command outputs the contents of a text file. You can use it to read brief files or to concatenate files together.
To append file1 onto the end of file2, enter:
cat file1 >> file2 To view the contents of a file named myfile, enter:
cat myfile
Because cat displays text without pausing, its output may quickly scroll off your screen. Use the less command (described below) or an editor for reading longer text files.
For more detailed information, see the Knowledge Base document In Unix, how do I combine several files into a single file?
cd
This command changes your current directory location. By default, your Unix login session begins in your home directory.
To switch to a subdirectory (of the current directory) named myfiles, enter:
cd myfiles
To switch to a directory named /home/dvader/empire_docs, enter:
cd /home/dvader/empire_docs To move to the parent directory of the current directory, enter:
cd .. To move to the root directory, enter:
cd /
To return to your home directory, enter:
cd
chmod
This command changes the permission information associated with a file. Every file (including directories, which Unix treats as files) on a Unix system is stored with records indicating who has permission to read, write, or execute the file, abbreviated as r, w, and x. These permissions are broken down for three categories of user: first, the owner of the file; second, a group with which both the user and the file may be associated; and third, all other users. These categories are abbreviated as u for owner (or user), g for group, and o for other.
To allow yourself to execute a file that you own named myfile, enter:
chmod u+x myfile To allow anyone who has access to the directory in which myfile is stored to read or execute myfile, enter:
chmod o+rx myfile You can view the permission settings of a file using the ls command, described below.
Note: Be careful with the chmod command. If you tamper with the directory permissions of your home directory, for example, you could lock yourself out or allow others unrestricted access to your account and its contents.
For more detailed information, see the Knowledge Base document In Unix, how do I change the permissions for a file?
cp
This command copies a file, preserving the original and creating an identical copy. If you already have a file with the new name, cp will overwrite and destroy the duplicate. For this reason, it's safest to always add -i after the cp command, to force the system to ask for your approval before it destroys any files. The general syntax for cp is:
cp -i oldfile newfile To copy a file named meeting1 in the directory /home/dvader/notes to your current directory, enter:
cp -i /home/dvader/notes/meeting1 . The . (period) indicates the current directory as destination, and the -i ensures that if there is another file named meeting1 in the current directory, you will not overwrite it by accident.
To copy a file named oldfile in the current directory to the new name newfile in the mystuff subdirectory of your home directory, enter:
cp -i oldfile ~/mystuff/newfile The ~ character (tilde) is interpreted as the path of your home directory.
Note: You must have permission to read a file in order to copy it.
date
The date command displays the current day, date, time, and year.
To see this information, enter:
date df
This command reports file system disk usage, (i.e., the amount of space taken up on mounted file systems). For each mounted file system, df reports the file system device, the number of blocks used, the number of blocks available, and the directory where the file system is mounted.
To find out how much disk space is used on each file system, enter the following command:
df
If the df command is not configured to show blocks in kilobytes by default, you can issue the following command:
df -k
du
This command reports disk usage (i.e., the amount of space taken up by a group of files). The du command descends all subdirectories from the directory in which you enter the command, reporting the size of their contents, and finally reporting a total size for all the files it finds.
To find out how much disk space your files take up, switch to your home directory with the cd command, and enter:
du The numbers reported are the sizes of the files; on different systems, these sizes will be in units of either 512 byte blocks or kilobytes. To learn which is the case, use the man command, described below. On most systems, du -k will give sizes in kilobytes.
find
The find command lists all of the files within a directory and its subdirectories that match a set of conditions. This command is most commonly used to find all of the files that have a certain name.
To find all of the files named myfile.txt in your current directory and all of its subdirectories, enter:
find . -name myfile.txt -print To look in your current directory and its subdirectories for all of the files that end in the extension .txt , enter:
find . -name "*.txt" -print In these examples, the . (period) represents your current directory. It can be replaced by the full pathname of another directory to search. For instance, to search for files named myfile.txt in the directory /home/user/myusername and its subdirectories, enter:
find /home/user/myusername/ -name myfile.txt -print On some systems, omitting the final / (slash) after the directory name can cause find to fail to return any results.
As a shortcut for searching in your home directory, enter:
find "$HOME/" -name myfile.txt -print For more detailed information, see the Knowledge Base document In Unix, what is the find command, and how do I use it to search through directories for files?
jobs
This command reports any programs that you suspended and still have running or waiting in the background (if you had pressed Ctrl-z to suspend an editing session, for example). For a list of suspended jobs, enter:
jobs Each job will be listed with a number; to resume a job, enter % (percent sign) followed by the number of the job. To restart job number two, for example, enter:
%2 This command is only available in the csh, bash, tcsh, and ksh shells.
kill
Use this command as a last resort to destroy any jobs or programs that you suspended and are unable to restart. Use the jobs command to see a list of suspended jobs. To kill suspended job number three, for example, enter:
kill %3 Now check the jobs command again. If the job has not been cancelled, harsher measures may be necessary. Enter:
kill -9 %3
less and more
Both less and more display the contents of a file one screen at a time, waiting for you to press the Spacebar between screens. This lets you read text without it scrolling quickly off your screen. The less utility is generally more flexible and powerful than more, but more is available on all Unix systems while less may not be.
To read the contents of a file named textfile in the current directory, enter:
less textfile The less utility is often used for reading the output of other commands. For example, to read the output of the ls command one screen at a time, enter:
ls -la | less In both examples, you could substitute more for less with similar results. To exit either less or more, press q . To exit less after viewing the file, press q .
Note: Do not use less or more with executables (binary files), such as output files produced by compilers. Doing so will display garbage and may lock up your terminal.
lpr and lp
These commands print a file on a printer connected to the computer network. The lpr command is used on BSD systems, and the lp command is used in System V. Both commands may be used on the UITS systems.
To print a file named myfile on a printer named lp1 with lpr, enter:
lpr -Plp1 myfile
To print the same file to the same printer with lp, enter:
lp -dlp1 myfile
Note: Do not print to a printer whose name or location is unfamiliar to you.
For more detailed information, see the Knowledge Base document In Unix, how do I print files and list or remove print jobs?
ls
This command will list the files stored in a directory. To see a brief, multi-column list of the files in the current directory, enter:
ls To also see "dot" files (configuration files that begin with a period, such as .login ), enter:
ls -a To see the file permissions, owners, and sizes of all files, enter:
ls -la If the listing is long and scrolls off your screen before you can read it, combine ls with the less utility, for example:
ls -la | less For more detailed information, see the Knowledge Base document In Unix, how do I list the files in a directory?
man
This command displays the manual page for a particular command. If you are unsure how to use a command or want to find out all its options, you might want to try using man to view the manual page.
For example, to learn more about the ls command, enter:
man ls To learn more about man, enter:
man man If you are not sure of the exact command name, you can use man with the -k option to help you find the command you need. To see one line summaries of each reference page that contains the keyword you specify, enter:
man -k keyword Replace keyword in the above example with the keyword which you want to reference. Also see the Knowledge Base document In Unix, what is the man command, and how do I use it to read manual pages?
mkdir
This command will make a new subdirectory.
To create a subdirectory named mystuff in the current directory, enter:
mkdir mystuff To create a subdirectory named morestuff in the existing directory named /tmp, enter:
mkdir /tmp/morestuff Note: To make a subdirectory in a particular directory, you must have permission to write to that directory.
mv
This command will move a file. You can use mv not only to change the directory location of a file, but also to rename files. Unlike the cp command, mv will not preserve the original file.
Note: As with the cp command, you should always use -i to make sure you do not overwrite an existing file.
To rename a file named oldname in the current directory to the new name newname, enter:
mv -i oldname newname To move a file named hw1 from a subdirectory named newhw to another subdirectory named oldhw (both subdirectories of the current directory), enter:
mv -i newhw/hw1 oldhw
If, in this last operation, you also wanted to give the file a new name, such as firsthw, you would enter:
mv -i newhw/hw1 oldhw/firsthw ps
The ps command displays information about programs (i.e., processes) that are currently running. Entered without arguments, it lists basic information about interactive processes you own. However, it also has many options for determining what processes to display, as well as the amount of information about each. Like lp and lpr, the options available differ between BSD and System V implementations. For example, to view detailed information about all running processes, in a BSD system, you would use ps with the following arguments:
ps -alxww
To display similar information in System V, use the arguments:
ps -elf
For more information about ps refer to the ps man page on your system. Also see the Knowledge Base document In Unix, what do the output fields of the ps command mean?
pwd
This command reports the current directory path. Enter the command by itself:
pwd
For more detailed information, see the Knowledge Base document In Unix, how do I determine my current working directory?
rm
This command will remove (destroy) a file. You should enter this command with the -i option, so that you'll be asked to confirm each file deletion. To remove a file named junk, enter:
rm -i junk
Note: Using rm will remove a file permanently, so be sure you really want to delete a file before you use rm.
To remove a non-empty subdirectory, rm accepts the -r option. On most systems this will prompt you to confirm the removal of each file. This behavior can be prevented by adding the -f option. To remove an entire subdirectory named oldstuff and all of its contents, enter:
rm -rf oldstuff
Note: Using this command will cause rm to descend into each subdirectory within the specified subdirectory and remove all files without prompting you. Use this command with caution, as it is very easy to accidently delete important files. As a precaution, use the ls command to list the files within the subdirectory you wish to remove. To browse through a subdirectory named oldstuff, enter:
ls -R oldstuff | less
rmdir
This command will remove a subdirectory. To remove a subdirectory named oldstuff, enter:
rmdir oldstuff Note: The directory you specify for removal must be empty. To clean it out, switch to the directory and use the ls and rm commands to inspect and delete files.
set
This command displays or changes various settings and options associated with your Unix session.
To see the status of all settings, enter the command without options:
set If the output scrolls off your screen, combine set with less:
set | less
The syntax used for changing settings is different for the various kinds of Unix shells; see the man entries for set and the references listed at the end of this document for more information.
vi
This command starts the vi text editor. To edit a file named myfile in the current directory, enter:
vi myfile The vi editor works fairly differently from other text editors. If you have not used it before, you should probably look at a tutorial, such as the Knowledge Base document How do I use the vi text editor? Another helpful document for getting started with vi is A quick reference list of vi editor commands.
The very least you need to know to start using vi is that in order to enter text, you need to switch the program from command mode to insert mode by pressing i . To navigate around the document with the cursor keys, you must switch back to command mode by pressing Esc. To execute any of the following commands, you must switch from command mode to ex mode by pressing : (the colon key): Enter w to save; wq to save and quit; q! to quit without saving.
w and who
The w and who commands are similar programs that list all users logged into the computer. If you use w, you also get a list of what they are doing. If you use who, you also get the IP numbers or computer names of the terminals they are using.
Terminal control characters for C-shell
^h, backspace erase previously typed character
^u erase entire line of input so far typed
^d end-of-input for programs reading from terminal
^s stop printing on terminal
^q continue printing on terminal
^z suspend currently running job; restart with bg or fg
DEL, ^c kill currently running program and allow clean-up before exiting
^\ emergency kill of currently running program with no chance of cleanup
Also see a list of special characters that should not be used in filenames.
Login and authentication
login access computer; start interactive session
logout disconnect terminal session
passwd change local login password; you must set a strong password that is not easily guessed
kinit obtain kerberos ticket for connections to other kerberized computers
kdestroy destroy kerberos tickets (authorizations)
keeptoken request longer lifetime for kerberos ticket so long-running jobs can access AFS files
Information
date show date and time
history list of previously executed commands
pine read or send email messages or networks news groups
msgs display system messages
man show online documentation by program name
info online documentation for GNU programs
w, who who is on the system and what they are doing
whoami who is logged onto this terminal
tpo show system stats and top CPU using processes
uptime show one line summary of system status
finger find out info about a user@system
whois look up information in the Stanford Directory
File management
cat combine files
cp copy files
ls list files in a directory and their attributes
mv change file name or directory location
rm remove files
ln create another link (name) to a file
chmod set file permissions
crypt encode/decode a file with a private key
gzip, gunzip compress/decompress a file
find find files that match specific criteria
Display contents of files
cat copy files to display device
more show text file on display terminal with paging control
head show first few lines of a file(s)
tail show last few lines of a file; or reverse line order
vi full-featured screen editor for modifying text files
pico simple screen editor for modifying text files
grep display lines that match a pattern
lpr send file to line printer
pr format file with page headers, multiple columns, etc.
diff compare two files and show differences
cmp compare two binary files and report if different
comm compare two files; show common or unique lines
od display binary files as eqivalent octal/hex codes
strings show printable text embedded in binary files
file examine file(s) and guess type: text, data, program, etc.
wc count characters, words, and lines in a file
Directories
cd change to new directory
mkdir create new directory
rmdir remove empty directory (remove files first)
mv change name of directory
pwd show current directory
Devices
df summarise free space on disk drive
du show disk space used by files or directories
Special character handling for C-shell (See man cs)
* match any characters in a file name
~user shorthand for home directory of user
$name substitute value of variable name
\ turn off special meaning of character that follows
' in pairs, quote string with special chars, except !
" in pairs, quote string with special chars, except !, $
` in pairs, substitute output from enclosed command
Controlling program execution for C-shell (See man csh)
& run job in background
DEL, ^c kill job in foreground
^z suspend job in foreground
fg restart suspended job in foreground
bg run suspended job in background
; delimit commands on same line
() group commands on same line
! re-run earlier commands from history list
jobs list current jobs
ps print process screen
kill kill background job or previous process
nice run program at lower priority
at run program at a later time
crontab run program at specified intervals
limit see or set resource limits for programs
alias create alias name for program (in .login)
sh, csh execute command file
Controlling program input/output for C-shell (See man csh)
| pipe output to input
> redirect output to a storage file
< redirect input from a storage file
>> append redirected output to a storage file
tee copy input to both file and next program in pipe
script make file record of all terminal activity
Email and communication
pine process mail with fill-screen menu interface or read USENET news groups
vacationsetup configure automatic email responses while you are on vacation
msgs read system bulletin board messages
mail send/read email; can be run by other programs to send exisiting files via email
uuencode, uudecode encode/decode a binary file for transmission via email
checkma check specific email addresses to see if they are valid, by contacting remote system(s)
finger translate real name to account name for email
whois look up email addresses in the Stanford Directory
talk interactive communication in real-time
rn read USENET news groups
Editors and formatting utilities
sed programmable text editor for data streams
vi full-featured editor for character terminals
emacs GNU emacs editor for character terminals
xemacs GNU emacs editory for X-Windows terminals
pico very simple text editor, same as pine Compose screen
fmt fill and break lines to make all same length
fold break long lines to specified length
X-Window client programs (output to X terminal or server)
xterm provide login shell window
xauth manipulate authorization files
xload show system load
xman full screen online manual viewer
pinex send or recieve mail messages
xemacs GNU emacs editor
gv interface to contol gs to display PostScript or PDF files on screen
xdvi display DVI files on X-Window (screen preview)
netscape web browser
gnuplot interactive data plotting on screen
TeX typesetting system
tex process TeX files to DVI (device independent) output
latex process LaTeX files to DVI
texpr process and print TeX and LaTeX in one step
dvips print DVI files on Postscript laser printer
xdvi display DVI files on X-Window (screen preview)
latex2html translate LaTeX files to HTML (for web pages)
Printing
lpr send file to print queue
lpq examine status of files in print queue
lprm remove a file from print queue
op lpc
abort qname abort print queue qname to clear printer (all files saved)
op lpc
start qname restart print queue qname
enscript convert text files to PostScript format for printing
Interpreted languages and data manipulation utilities
sed programmable text editor for data streams
awk pattern scanning and processing language; 1985 vers.
perl Practical Extraction and Report Language
sort sort or merge lines in a file(s) by specified fields
tr translate characters
cut cut out columns from a file
paste paste columns into a file
dd copy data between devices; reblock; convert EBCDIC
Graphics and mapping
gnuplot interactive data plotting; outputs to PostScript or X-windows
GMT general 2D and 3D data processing and plotting software package; also plots maps
gs "ghostscript" converter displays PostScript files on X-window displays or other devices
Networking/communications
klogin remote login to kerberized computer; encrypted
krsh execute single command on remote kerberized computer; encrypted
krcp remote file copy to/from kerberized computer; encrypted
ssh remote login/command execution; encrypted
scp remote non-interactive file copy; encrypted
sftp remote interactive file copy; encrypted
telnet remote network login - plain text password
ftp network file transfer program - plain text passwords
rlogin remote login to "trusted" computer that is not kerberized
rsh execute single command on remote "trusted" computer
rcp remote file copy to/from "trusted" computer
host find IP address for given host name, or vice versa
netscape web browser for X-window terminals/servers
lynx web browser for character based (text-only) terminals
kermit transfer files over modem connections
gzip, gunzip compress/decompress a file
tar combine multiple files/dirs into single archive
uuencode, uudecode encode/decode a binary file for transmission via email
Compilers, interpreters and programming tools
csh command language interpreter (C-shell scripts)
ksh command language interpreter (Korn-shell scripts)
sh command language interpreter (Borne-shell scripts)
f77 Compaq(HP) Fortran 77 compiler
f95 Compaq(HP) Fortran 90/95 compiler
f2c convert fortran source code to C source code
cc, c89 Compaq(HP) ANSI 89 standard C compiler
cxx Compaq(HP) C++ compiler
gcc GNU C compiler
g++ GNU C++ compiler
pc Compaq(HP) Pascal compiler
dbx command-line symbolic debugger for compiled C or Fortran
ladebug X-window symbolic debugger for compiled C or Fortran
make recompile programs from modified source
gmake GNU version of make utility
cflow generate C flow graph
error analyze and disperse compiler error messages
Programming libraries (see man library_name)
lapack Fortran 77 routines for numerical linear algebra (supersedes LINPACK and EISPACK)
X routines to interface with X window system (no man page -- get the X Toolkit book)
dbm database routines
xdr library routines for external data representation
netcdf routines for machine independent data representation
Tape manipulation and archiving
mt manipulate tape drive and position tape
dd unformatted tape read and write; file conversion
tar archive disk files on tape or disk
ltf read/write ANSI standard label tapes
Geology programs
supcrt92 thermodynamic properties of high P/T reactions
diagram calculate activity phase diagrams from log K values
UNIX tutorial:
http://www.injunea.demon.co.uk/pages/page203.htm
http://cals.arizona.edu/ecat/web/permissions.html
http://cals.arizona.edu/ecat/classes/videoclips.html
http://www.oreillynet.com/cs/user/view/cs_msg/33720