alias cp="cp -i", set alias name for command

at

• execute job at specific time
• at -l or atq: show job queue
• atrm: delete job
• Ctrl-D, stop commands edit
• +2 hours, execute in two hours
• -f file, set file as input
• /etc/at.allow, only users who are listed in this file may execute
• /etc/at.deny, all users may use the at command except those listed in this file

apropos, search command in whatis database

awk, extract content from file

bc, an arbitrary precision calculator language

basename, strip directory and suffix from filenames

batch

• almost same as at command with low priority
• atq, display job queue
• Ctrl+d, stop input

bg, reactive a suspended program in the background

bzip2

• bzip2 -9 -k myfile.doc: compress file
• bzip2 -d myfile.doc.bz2: uncompress file
• -k: keep old file

bunzip2

• uncompress .bz2 file
• -v: show uncompress process
• -k: keep old file

cal

• calender
• -y: year
• -m: month
• cal 07 1999: show calender in July, 1999

cat

• set -o clobber, avoid to overwrite existing file
• cat a.txt: show a.txt
• cat a.txt b.txt > c.txt: combine a.txt and b.txt to form c.txt, delete the previous content in c.txt
• cat a.txt b.txt >> c.txt: attach the content in a.txt and b.txt to c.txt
• cat > a.txt: input content into a.txt from the keyboard
• cat << EOF, instruct the shell to use the text up to the next occurrence of this character sequence as the standard input

cd

• cd /: switch to root
• cd ~: switch to home
• cd ..: switch to upper layer
• cd .: switch to current layer

chattr

• change file or directory attributes
• sudo chattr +i test
• sudo chattr -i test

chfn

• Change user information

chgrp

• change group
• chgrp manager prilist.doc

chmod

• owner, group, other
• a: all; u: owner; g: group; o: other
• x: execute; r: read; w: write
• chmod g+rw mydoc: give reading and writing permission for group
• -R: change permission for all sub directory

chown

• change owner
• chown lisa acclist.doc

chsh

• change user shell
• -l: list shell in the system

clear

cmp, compare two files and return first different character

column, column formatter

colrm 2 4 < filename, removes the second through fourth characters from each line of the text file filename

compress

• compress taipei24.pcf: compress file to .Z file
• -d: uncompress .Z file
• -v: show compress process

comm

• compare two files
• -12: show line in both file
• -23: only show line in first file

cp

• -b: make a backup of each existing destination file
• -r: copy directory
• -R: recursive copy
• -p: keep same access priority
• -i: ask before cover
• -v: show copy process
• -u: only cover older file
• -l: creat link

cpio

• find . | cpio -o -v -O output, pack all file in current directory into output
• cpio -i -v -I output, unpack output file

cron

• Cron Tutorial
• service cron start, start cron
• crontab -u lchen file, execute command for user lchen
• crontab -r, current crontab will be removed
• crontab -l, list user's crontab
• */1****ls>>/tmp/ls.txt
  • *(minute) *(hour) *(date) *(month) *(week day)
  • /, times per unit
  • -, figure value range
  • ,, seperate several number
  • #, comment
• shopt, permits changing shell options, -s, set, -u, unset

curl, a client to get and send documents

cut

• cut part of the file
• ls -al | cut -b25-, output position 25 and after for each line
• cut -d: -f1,5 /etc/passwd, use : as delimitor and output 1 and 5 fields
• cut -d: -f1-5 /etc/passwd, output 1-5 fields
• cut -d: -f5- /etc/passed, output 5th field and fields after it
• ls -al | cut -d' ' -f1,5, output the first column and fifth column

date

• Tutorial
• date "+%Y:%m:%d: Time:%H:%M:%S"
• date -d "nov 22", display the date of Nov. 22 in this year
• date -d '2 weeks', get the date after two weeks
• date -d 'next monday', get the date of next monday
• date -d 'dec 14 -2 weeks', get the date of two weeks before Dec. 14
• date -d '-100 days', date before 100 days

df

• show hard disk space
• -h: show size by GB
• -T: show file system type

diff

• -b, ignore space change
• -B, ignore blank lines
• -I, ignore case sensitive
• -r, recursive two direcotries
• -y, compare two file by two column
• diff -urN old/ new/ > mysoft.patch
• patch -p0 < mysoft.patch

dir

dirname file, display path name

dircolors, show color set up

du

• -k: count by k
• -m: count by m
• -s: show space occupation in current directory

echo

• echo $PATH: show executable file path
• echo $USER: show current user
• echo $HOME: show home directory
• echo $SHELL: show shell
• echo $BROWSER: show browser environment variable

editres, used for displaying and editing of X resources

env

• set up environment variable

eval, replace, then execute the command replaced

• test.txt, "hello shell world!"
• myfile="cat test.txt"
• echo $myfile #result:cat test.txt
• eval echo $myfile #result:hello shell world!

exec < filename, implement command and return

export PATH, export environment variable

expr

• expression evaluator
• expr 3 + 5, 8
• expr 5 \* 3, 15
• expr substr $string $positon $length, extrace substring of string
• expr length $string, get the length of string
• expr match "$string" '$substring', expr "$string" : '$substring', length of matching substring at beginning of string
• expr index $string $substring, numberical position in $string of first character in $substring that matches

dolphin, file manager

factor, decompose an integer into prime factors

fdisk

• disk tool

fg, put job back to the foreground

file

• check file type

find

• Example
• find . -name my\*, search by name
• find / -name "my*" -print: serach by name under root directory
• find /usr -atime -3 -print: search files saved within 3 days
• find /usr -ctime -5 -print: search files changed within 5 days
• find /doc -user jacky -print: search by user name
• find ./ -name 'main*' -exec more {} \;: search main* and show it
• find ./ -perm 644, search by permission
• -user, search by user name
• -group, search by group name
• -mtime, search by modify time, -n within n days, +n before n days
• -atime, search by access time, -n wihtin n days, +n before n days
• -ctime, search by create time
• -type, search by type
• -size, search by size
• -newer f1 !f2, search file which is newer than f1 and older than f2
• -ok: same as -exec except has prompt
• -ls: list search results
• -a: and
• -o: or
• !: not
• -xtype, file type
• find ./ -name testFile -exec more {} \;
• find . -name \* -exec echo rm {} \;, display the files that can be deleted
• find . -name \* -exec rm {} \;, delete files
• find . -name \* -ok rm {} \;, prompt before the command is executed
• rm $(find . -name \*), delete files

finger

• show user information
• finger lchen

fmt, simple-minded file formatter

fold, filter that wraps lines of input to a specified width

free, check system memory

ftp

• ls: list directory
• cd: change directory
• lcd: change local directory
• close: close ftp session
• get: get file to local machine
• put: upload file to remote machine
• quit: quit ftp

grep

groupadd

• add group
• groupadd -g 1001 group2, create group group2 and assign GID

groupdel, del group

groupmod -g 10000 -n group3 group2, set GID and change group name to group3

groups

• show current group

gunzip

• -f: cover same name file
• -r: uncompress the file in the sub directory
• -v: show uncompress process

gzip

• gzip -9 big1.bmp: compress to minimum file
• gzip -1 big1.bmp: compress by fast way
• gzip big1.bmp: default parameter is -6
• -v: show compress process
• -r: compress the files in the directory
• -d: uncompress the file

head

• show first severl lines of file
• head -3 example.c

host

• displays the information on hosts or domains
• host www.google.com

hostname

• show host name
• hostname is saved /etc/hostname

id, show current user id and current group id, groups that current user belongs to

ifconfig

• ifconfig eth0 down, equals to ifdown eth0, inactive ethernet
• ifconfig eth0 up, equals to ifup eth0, active ethernet
• ifconfig eth0, show ip information of eth0
• ifconfig, show all net information

info, equals to man command

infocmp, prints out extensive information about the current terminal

ip, show/manipulate routing, devices, policy routing and tunnels

• ip addr, show ip address

jobs, show jobs running in the background

join

• join file1 file2, combine two files by same column

kill

• -15: terminal process in an orderly way
• -2: interrupt process, a process can ignore this signal
• -9: force to kill process
• 0: to stop all process except your shell
• -l: list signal which is saved in /usr/include/signal.h

ldconfig, configure share library

ldd

• Check the library that program needs during execution
• ldd /usr/bni/xterm

less, display file

ln

• ln targetfile linkname
• default is hard line which sign several link for one file
• -f: delete previous link before create new link
• -s: symbolic link which like fast link in windows, can link directory

locate

• search library file
• updatedb, update database for locate

login

logout

lpr

ls

• -l, use a long listing format
• -a, do not ignore entries starting with .
• -d, list directory entries instead of contents, and do not dereference symbolic links
• -R, list subdirectories recursively
• --color: color the directory and file if default is no color
• -F: mark executable file and directory

lsattr

• list file and directory attributes
• a, only append allowed
• c, compress file
• d, file is not saved by dump
• i, file is immutable: no deletion, renaming, writing, and linking
• s, secure deletion of file
• S, Synchronous writing of modifications
• u, allow undelete

man

• man date: check the manual of date
• man 1 passwd, show passwd command in section 1
• man 5 passwd, show passwd command in section 5
• man -k passwd, show a list of man pages that have keyword in their one-line synopses
• man -a passwd, show all man pages about passwd one after the other

mandb

• add additional man pages to your system, rebuild this file on Ubuntu, SUSE
• makewhatis, on Red Hat
• catman -w, Solaris, HP-UX, AIX

manpath, default search path for command man

mesg, allow/not allow reveive message from others

mkbootdisk

• create reboot disk

mkdir

• mkdir -p /company/saledept/jacky: build severl layer directory
• mkdir -m 755 jacky: sign access priority when creat the directory

mke2fs

• format disk

more, display file

mount

• mount -tsmbfs //userdata.cs.odu.edu/grad/lchen /mnt/Z -o username=lchen,password=PASSWARD,rw,file_mode=0777,dir_mode=0777, mount the network disk
• mount /dev/sdb1 /media/usb: mount usb disk under root
• -t: specify format, ext2, msdos, iso9660, vfat

mtools

• Compitable commands with MS-DOS

mv

• -b, make a backup of each existing destination file
• -i: ask before cover
• -v: show moving process

netstat

• -n: show ip instead of address
• -t: show tcp information
• -u: show udp information

Network

• ./network under /etc/rc.d/init.d
• ./network restart: restart network

newgrp

• switch group when user belongs to several groups
• id, show the user id and current group id, groups that user belongs to
• newgrp test, switch current group to test group

nice

• Nice Tutorial
• -20-19, program priority level
• nice, show default priority level
• need administrator privilege
• nice --1 program, default priority level minus one
• nice -n -13 program, set priority level number

nl, line numbering filter

nohup

• still run the job when user log out
• nohup sort sales.dat &: run sort ignoring user quitting

nslookup

• check ip address
• local: check local ip
• www.google.com: check google server ip

okular

• open pdf file

ooffice

• oocalc, excel
• oowriter, word
• oomath, formula edit
• ooweb, dreamweaver
• ooimpress, powerpoint
• oobase, database
• oodraw, painter

ping

• ping www.google.com, check if a host is alive
• -c: set up ping times
• -v: show ping process

passwd

• passwd: change current user password
• passwd tommy: change password for tommy
• -l: lock account
• -u: unlock account
• -d: not password
• -f: force to change password when log in next time

paste

• paste -d -s -file1 file2
• -d, figure delimitor
• -s, cobmine files by merging line instead of combining line by line

patch

• update software
• diff -urn old/ new/ > mysoft.patch
• patch -p0 < mysoft.patch,/li>

printenv, print environment variable value

Printer

• /etc/init.d/cups restart, restart the printer scheduler which is shut down after restart

ps

• -a: list all provesses which is running
• -au: list detail information
• -e: list all processes
• -l: show detailed informaiton
• -x: show executing processs
• ps -ef | grep lchen, show all processes owned by lchen
• ps -auxw | grep bash, show all processes with a process name of bash

pstree, display a tree of processes

pwd, show current path

rclock

• clock

rdesktop -g 1024*768 -d 24 vclab.cs.odu.edu, remote desktop control

read

• read -p "Press any key: " name, display prompt
• read -t 1, set up waiting time
• read -n1, read one type and exit

readlink, disclose the file that a symbolic link points to

reboot, reboot computer

rename

• rename multiple files
• rename 's/\.bak$//' *.bak
• renmae 'y/A-Z/a-z/' *

renice

• Renice Tutorial
• renice -5 -p 5200, change running program priority level to -5
• -g, reset priority level for all programs of the group
• -p, reset priority level for program
• -u, reset priority level for all programs of the user

reset, reset terminal parameters and clear text screen

resize, echoes commands necessary to set $TERM and $TERMCAP to duplicate the size (dimensions) of the current terminal

rm

• -i: ask before delete
• -v: show deleting process
• -r: delete directory
• -f: delete without asking

rmdir

route, show internet route

rpm

• -i: install
• -test: test install
• -replacepkgs: force to install the software which has been installed
• -ignoreos: ignore safty checking
• -v: show extra information
• -vv: show debug information
• -root DIRECTORY: figure out install directory
• -e: delete software package
• -U: update the software

screen

• -r, resume screen when remote connection is abnormal broken

script, records (saves to a file) all the user keystrokes at the command-line in a console or an xterm window, exit to stop

sed, stream editor

seq

• seq 10, output 1 to 10
• seq 2 7, output 2 to 7
• seq 1 2 20, output 1 to 20 with step 2

service

• service --status-all, list all service
• service program restart, start a service

shopt, permits changing shell options, -s, set, -u, unset

sleep, pause and run the command later

• (sleep 1800; echo "Lunch time ...") &

sort

• sort and output
• -d, ignore specific character, such as %
• -f, ignore capital or lower case characters
• -u, ignore repeat line
• -n, sort by value
• -t, figure out delimiter
• -r, reverse sort
• sort -nk 5, sort file by the fifth column
• sort +1 -2 -n file, sort second column by real value instead of the number at first position

shutdown

• shutdown -h now: shut down right now
• shutdown -h +30: shut down in 30 minutes
• shutdown -h 12:10: shut down at 12:10
• shutdown -c: cancel the sutdown command
• shutdown -r now: reboot computer
• shutdown -k +10 'content': sent out a shut down warning, not real shut down

stat, similar to ls, list file size, access, Uid, Gid, access time

ss, show net information

ssh

• ssh lchen@hpcq.cs.odu.edu, log in hpcq
• ssh lchen@hpcq.cs.odu.edu ls, implement ls on hpcq

strings, filter character strings out of binary files

• -n, return strings which are at lease the numer of that interger in length
• -t, return the offset position for each line on which one or more strings are found

su

sudo

• make user has permission to perform root command
• -l: check what kind of command can be executed by current user
• -h: show sudo parameter
• -s: figure out shell
• -k: enforce to ake password when implement next sudo command

tail

• show several tail line of file
• tail -20f example.c

tar

• tar -cf new1.tar my1*.doc: pack the files but no compress
• tar -zcf new1.tar.gz my1*.doc: pack and compress the file by gzip
• tar -Zcf new1.tar.Z my1*.doc: pack and compress the file by Compress
• tar -zxvf onepackage.tgz: uncompress the files from package
• -r: add file to the packed file
• -r: update file in the packed file
• -c, creat
• -x, unpack a file
• -t, check tar file
• -z, compress by gzip
• -Z, compress by Compress
• -j, check bzip2 character
• -v, show document when exectue packing
• -f, fellow the document name
• -p, use previous character
• -P, sign the path
• tar -cvf file.tar ./file
• tar -zcvf file.tar.gz ./file
• tar -jcvf file.tar.bz2 ./file

tee

• read data from standard input and output into file
• -a, append to file
• date | tee file1 file2

telinit

• change system running level
• who -r, check running level
• 0, halt
• 1, single user mode
• 2, multiuser, without NFS
• 3, full multiuser mode
• 4, unused
• 5, X11
• 6, reboot

test, check file types and compare values

time

• time, show program running time
• /usr/bin/time, show the exit status of the command and the elapsed time

top

• show top process running
• -i: do not show spare process
• -r: adjust process priority level
• -u: show processes of the specific user

touch, create a file

tr

• tr Tutorial
• transform characters
• -c, complement the set of characters in string
• -d, delete character
• -s, delete repeat character
• tr -cs "[:alpha:]" "\n" < /path/to/file, creater a list of the words in /path/to/file, one per line
• \\, "\"
• \a, alarm
• \b, backspace
• \f, change page
• \n, new line
• \r, enter
• \t, tab
• \v, vertical table character
• [a-z], [A-Z], [0-9]
• [:alnum:], all alphabets and all numbers
• [:alpha:], all alphabets
• [:blank:], all blank space
• [:cntrl:], all control characters
• [:digit:], all numbers
• [:graph:], all printable characters except blank
• [:lower:], all lower case characters
• [:print:], all printable characters
• [:punct:], all delimiter characters
• [:space:], all space
• [:upper:], all capital letters
• tr "h2" "3x" < sname, change "h" to "3", "2" to "x"
• cat file | tr "abc" "xyz" > new_file, replace "abc" with "xyz"
• grep \* output.txt | tr '[:lower:]' '[:upper:]'
• cat testFile | tr [a-z] [A-Z]
• cat file | tr [A-Z] [a-z]
• cat file | tr -d "Snail" > new_file, delete "Snail" in the strings
• cat file | tr -d "\n\t" > new_file, delete \n and \t
• cat file | tr -s [a-zA-Z] > new_file, delete repeat characters
• cat file | tr -s "\n" > new_file, delete empty lines
• grep \* output.txt | tr -d '\n', delete all enter characters and print out

tracepath, trace the path to specific address

tree, display the tree structure of a folder

type, show the type of the command

ulimit -a, show file size limit

umask, sets the file mode creation mask

• set up default permission for new file and new directory
• default value is 022
• directory, 777-022
• file, 666-022
• umask, show umask value, 0022
• umask 002, remove write for others, value is changed to 0002

umount

• umount /media/usb: remove usb disk under root

uname

• -a: show system information

uncompress

• uncompress one.Z

uniq

• uniq [option] [input] [output], remove the continuous repeat lines
• -c: show the number of occurrences
• -d: only print duplicate lines
• -u: only show the line without repeat

unzip

• unzip onepackage.zip a*.doc: uncompress part of files
• -f: uncompress updated files
• -u: uncompress updated files and none-exist files
• -o: uncompress and cover previous files
• -n: uncompress none-exist files
• -j: all uncompress under current directory, not mater where the files are
• -d: uncompress under specfic directory

uptime, check how long the system has been running

userdrake

• add, delete user and set up group

userinfo

• show user information

usermod

• -s, change shell
• useradd -s /bin/sh sam, change shell to sh for sam
• -d, change home directory
• -g, change group

usermount

• mount device

userpasswd

• change password for current user

users

• show current user

useradd

• -m: create directory
• -g: alocate group
• -s: figure out shell
• -u: figure out user number
• adduser -d /usr/sam -m sam: create account for sam
• adduser -s /bin/sh -g group -G adm,root gem: create account for gem

userdel, delete user account

usleep, pauses #N microseconds

updatedb, update database for locate

uptime, show system load average, average processes number in the queue

vdir

vmstate, check memory

w, check who is logged in the system

wall, send message to all users who are connected to this machine

wc

• wc names, get a count of the total number of lines, words, and characters of information contained in a file
• -c: count character number
• -l: count line
• -L: count length of maxmium line

whatis, serach system command database

whereis

• whereis bzip2: show command directory and the directory for the man page

which, show command place

who

• show current user information
• -b: show last log in time
• -a: show all information
• -r: show running level

whoami

whois, specific domain information

write

• send message to other persons
• who, check who is connecting to this machine
• write lchen, start write and send message to lchen

xargs, create command line

• find /etc -type f -print | xargs grep LUENE02

xdpyinfo, information about the X server

xev, displays the X events

xine

• Moive player

xhost

• xhost, display the machines that are allowed to access current machine
• xhost +, allow all machines access current machine
• xhost + hpcq.cs.odu.edu, add machine to allowed list
• xhost - hpcq.cs.odu.edu, remove machine from allowed list

xkill

• xkill -id 0*340000b, kill creator of resource 0*340000b

xlsclients

• list the display clients and program
• xlsclients -l -a, list all information

xmag, magnify parts of the screen

xman, display of man pages

xmodmap, used to change the keyboard mapping

xmore, more with graphic interface

xprop, display information about clients

xrandr, check monitor resolution

xset, set up keyboard click, sound, or the screen saver

xwd, save the current screen contents in a file

xwininfo

• display window information
• -geometry 81*24+0+0, window of 81 char by 24 line lines in the upper left corner of the screen

zdump

• zdump EST, echoes the time in a specified time zone

zip

• zip new1.zip my1*.doc: compress and pack files
• zip -d new1.zip my18.doc: delete file from compress file
• zip -g new1.zip my32.doc: add file into compress file
• zip -u new1.zip my2*.doc: update file in the compress file
• -r: compress directory

Device

• Touchpad
  • in /ect/X11/xorg.conf
  • Section "InputDevice"
  • Identifier "Synaptics Touchpad"
  • Driver "synaptics"
  • Option "SendCoreEvents" "true"
  • Option "Device" "/dev/psaus"
  • Option "Protocol" "auto-dev"
  • Option "HorizEdgeScroll" "0"
  • Option "SHMConfig" "0"
  • EndSection
  • synclient touchpadoff=1, turn off touchpad
  • synclient touchpadoff=0, turn on touchpad