UNIX - USEFUL COMMANDS
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T his quick g uide lists commands, including a syntax and brief description. For more detail, use:
$man command
Files and Directories:
T hese commands allow you to create directories and handle files.
Command Desc ription
cat Display File Contents
cd Chang es Directory to dirname
chg rp chang e file g roup
chmod Chang ing Permissions
cp Copy source file into destination
file Determine file type
find Find files
g rep Search files for reg ular expressions.
head Display first few lines of a file
ln Create softlink on oldname
ls Display information about file type.
mkdir Create a new directory dirname
more Display data in pag inated form.
mv Move (Rename) a oldname to newname.
pwd Print current working directory.
rm Remove (Delete) filename
rmdir Delete an existing directory provided it is empty.
tail Prints last few lines in a file.
touch Update access and modification time of a file.
Manipulating data:
T he contents of files can be compared and altered with the following commands.
Command Desc ription
awk Pattern scanning and processing lang uag e
cmp Compare the contents of two files
comm Compare sorted data
cut Cut out selected fields of each line of a file
diff Differential file comparator
expand Expand tabs to spaces
join Join files on some common field
perl Data manipulation lang uag e
sed Stream text editor
sort Sort file data
split Split file into smaller files
tr T ranslate characters
uniq Report repeated lines in a file
wc Count words, lines, and characters
vi Opens vi text editor
vim Opens vim text editor
fmt Simple text formatter
spell Check text for spelling error
ispell Check text for spelling error
ispell Check text for spelling error
emacs GNU project Emacs
ex, edit Line editor
emacs GNU project Emacs
emacs GNU project Emacs
Compressed Files:
Files may be compressed to save space. Compressed files can be created and examined:
Command Desc ription
compress Compress files
g unzip Uncompress g zipped files
g zip GNU alternative compression method
uncompress Uncompress files
unzip List, test and extract compressed files in a Z IP archive
zcat Cat a compressed file
zcmp Compare compressed files
zdiff Compare compressed files
zmore File perusal filter for crt viewing of compressed text
Getting Information:
Various Unix manuals and documentation are available on-line. T he following Shell commands g ive information:
Command Desc ription
apropos Locate commands by keyword lookup
info Displays command information pag es online
man Displays manual pag es online
whatis Search the whatis database for complete words.
yelp GNOME help viewer
Network Communication:
T hese following commands are used to send and receive files from a local UNIX hosts to the remote host around
the world.
Command Desc ription
ftp File transfer prog ram
rcp Remote file copy
rlog in Remote log in to a UNIX host
rsh Remote shell
tftp T rivial file transfer prog ram
telnet Make terminal connection to another host
ssh Secure shell terminal or command connection
scp Secure shell remote file copy
sftp secure shell file transfer prog ram
Some of these commands may be restricted at your computer for security reasons.
Messag es between Users:
T he UNIX systems support on-screen messag es to other users and world-wide electronic mail:
Command Desc ription
evolution GUI mail handling tool on Linux
mail Simple send or read mail prog ram
mesg Permit or deny messag es
parcel Send files to another user
pine Vdu-based mail utility
talk T alk to another user
write Write messag e to another user
Prog ramming Utilities:
T he following prog ramming tools and lang uag es are available based on what you have installed on your Unix.
Command Desc ription
dbx Sun debug g er
g db GNU debug g er
make Maintain prog ram g roups and compile prog rams.
nm Print prog ram's name list
size Print prog ram's sizes
strip Remove symbol table and relocation bits
cb C prog ram beautifier
cc ANSI C compiler for Suns SPARC systems
ctrace C prog ram debug g er
g cc GNU ANSI C Compiler
indent Indent and format C prog ram source
bc Interactive arithmetic lang uag e processor
g cl GNU Common Lisp
perl General purpose lang uag e
php Web pag e embedded lang uag e
py Python lang uag e interpreter
asp Web pag e embedded lang uag e
CC C++ compiler for Suns SPARC systems
g ++ GNU C++ Compiler
javac JAVA compiler
appletvieweir JAVA applet viewer
netbeans Java integ rated development environment on Linux
sqlplus Run the Oracle SQL interpreter
sqlldr Run the Oracle SQL data loader
mysql Run the mysql SQL interpreter
Misc Commands:
T hese commands list or alter information about the system:
Command Desc ription
chfn Chang e your fing er information
chg rp Chang e the g roup ownership of a file
chown Chang e owner
date Print the date
determin Automatically find terminal type
du Print amount of disk usag e
echo Echo arg uments to the standard options
exit Quit the system
fing er Print information about log g ed-in users
g roupadd Create a user g roup
g roups Show g roup memberships
homequota Show quota and file usag e
iostat Report I/O statistics
kill Send a sig nal to a process
last Show last log ins of users
log out log off UNIX
lun List user names or log in ID
netstat Show network status
passwd Chang e user password
passwd Chang e your log in password
printenv Display value of a shell variable
ps Display the status of current processes
ps Print process status statistics
quota -v Display disk usag e and limits
reset Reset terminal mode
script Keep script of terminal session
script Save the output of a command or process
setenv Set environment variables
stty Set terminal options
time T ime a command
top Display all system processes
tset Set terminal mode
tty Print current terminal name
umask Show the permissions that are g iven to view files by default
uname Display name of the current system
uptime Get the system up time
useradd Create a user account
users Print names of log g ed in users
vmstat Report virtual memory statistics
w Show what log g ed in users are doing
who List log g ed in users
