Unix Commands

('#' prompt denote root user, '$' prompt denote non-root user)

List directories / files

$ ls -al

List directories / files, sort by time

$ ls -alt

List running process

$ ps aux

List running process sort by cpu usage, checking RAM size, swap size

$ top

or

$ free -m

List who is logged On

$ w

Display calendar

$ cal

or

$ cal 2013

Check which shell is currently in

$ ps -p $$

or

$ echo $SHELL

List uid, gid, group etc

$ id

List user using pdb database

# pdbedit -L -v

Export path ($PATH is existing path, /usr/lib is newly added)

$ PATH=$PATH:/usr/lib ; export PATH

View File

$ more /etc/inittab

$ less /etc/inittab

$ cat /etc/inittab

Disk usage, totally

$ du -ch | grep total

Disk usage for all subfolder, (h=human readable, k=kilo)

$ du -sh *

Make bash print out each command it is going to run before it runs it.

$ set -x

Make bash vim mode (Or put below in .bashrc).

$ set -o vi

Create new env variable

$ export https_proxy="https://xx.xx.xx.xx:yyyy/"    (bash)

$ setenv https_proxy "https://xx.xx.xx.xx:yyyy/"    (csh, tcsh)

Delete env variable

$ unset https_proxy

$ env -u https_proxy

Revert/unset all env variable to login condition.

$ env -i bash

Ignore the alias and just run ls, using "\"

$ \ls -alF

Expand/reveal currently typed command alias (bash OK but zsh/csh/tcsh NG)

$ Ctrl + Alt + E

Searching through the Command History (CTRL-R)

$ CTRL+r

(reverse-i-search)`':

After you have typed what you are looking for, use the CTRL+r key combination to scroll backward through the history.

Shell shortcut, go start of line

Ctrl + a

Shell shortcut, go end of line

Ctrl + e

Shell shortcut, move forward one word

Alt + f

Shell shortcut, move backward one word

Alt + b

Shell shortcut, delete word from cursor to start of word

Ctrl + w

Shell shortcut, delete word from cursor to end of line

Esc + k

Shell shortcut, clear screen

Ctrl + l

Change "ls" file and directory color (put below at ~/.bashrc)

LS_COLORS='rs=0:di=01;33:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:';

export LS_COLORS

Legend

di = directory

fi = file

ln = symbolic link

pi = fifo file

so = socket file

bd = block (buffered) special file

cd = character (unbuffered) special file

or = symbolic link pointing to a non-existent file (orphan)

mi = non-existent file pointed to by a symbolic link (visible when you type ls -l)

ex = file which is executable (ie. has 'x' set in permissions).

Effects

00  Default colour

01  Bold

04  Underlined

05  Flashing text

07  Reversetd

08  Concealed

Colours

30  Black

31  Red

32  Green

33  Orange

34  Blue

35  Purple

36  Cyan

37  Grey

Backgrounds

40  Black background

41  Red background

42  Green background

43  Orange background

44  Blue background

45  Purple background

46  Cyan background

47  Grey background

Extra colours

 90 Dark grey

 91 Light red

 92 Light green

 93 Yellow

 94 Light blue

 95 Light purple

 96 Turquoise

 97 White

100 Dark grey background

101 Light red background

102 Light green background

103 Yellow background

104 Light blue background

105 Light purple background

106 Turquoise background

107 White background

di=5;31;42

mean flashing red text with a green background

Add user, change the default password

# adduser username

# passwd username

Delete user, and its home directory

# userdel -r username

Create group, add some user in

$ addgroup cvsgrp

$ adduser username cvsgrp

or

$ usermod -G cvsgrp username

Add samba user, restart samba service

# smbpasswd -a keanheong

List samba user, if smb.conf contain passdb backend = tdbsam

# vim /var/lib/samba/private/passdb.tdb

To make samba able to access to rootfs

vim /usr/local/etc/smb.conf (FreeBSD)

vim /etc/samba/smb.conf (CentOS)

[global]

    unix extensions = No

    wide links = Yes

Then create s symbolic link at user home directory

ln -s / rootfs

Restart samba service (root user)

# service smb restart

Restart samba service (non-root user)

$ sudo /sbin/service smb restart

Check samba user

# pdbedit -L -v

Suspend and bring back

Ctrl+Z to suspend it and fg 1 or fg 2 to bring it on the

foreground.

Open last cmd in editor and run the edited version

fc

Find IP address

nslookup www.google.com

Converting current date into Julian format

date +%j

date -d "2011/07/13" +%j

date +%Y%m%d

date -d "-2 days"

date -d "2 days"

date +%Z

Execute last "ls" cmd

!ls

Open last file in vim

!vim

!! mean last cmd

sudo !!

cmd that start with space did not goes into history

Create file with suffix date

touch file-$(date -I)

Find filename and directory

$ find . -name "*jfb*" -print

Find filename only

$ find . -name "*jfb*" -type f

Find giant file

$ find . -type f -size +100M

Find directory only

$ find . -name "*jfb*" -type d

Find file/directory with group permission not write

$ find . ! -perm /g+w

Find files with 0 byte in size

$ find . -size 0

Find file/directory with group permission not write, change to write, handle filename with space

$ find . ! -perm /g+w | xargs -I{} chmod g+w {}

Find file/directory with group not equal to mail

$ find . ! -group mail

Find file/directory with group not equal to mail, change it to mail, handle filename with space

$ find . ! -group mail | xargs -I{} chgrp mail {}

Find in file

$ find . -exec grep -q "libstd*" '{}' \; -print

Find in file

$ grep -Hrns "libstd*" .

Find in file, match whole word

$ grep -Hrnws "libstd" .

Find in file, include file types

$ grep -Hrns --include=\*.{c,h} "libstd*" .

or

$ grep -Hrns --include="*.{c,h}" "libstd*" .

Find in file, exclude file types

$ grep -Hrns --exclude=\*.{a,o,out,lib,swp} "libstd*" .

or

$ grep -Hrns --exclude="*.{a,o,out,lib,swp}" "libstd*" .

Find in file, exclude directory

$ grep -Hrns --exclude-dir="\.svn" "libstd*" .

add this line to ~/.bashrc or ~/.bash profile

export GREP_OPTIONS='--exclude-dir=.svn --color=auto --line-number --with-filename --recursive'

Find in file type *.c

$ grep -Hrns "libstd*" `find . -name "*.c"`

or

$ find . -name "*.h" -exec grep -Hrns "libstd" {} \;

Find not contain in file

$ grep -Hrn -v "libstd*" .

Find Duplicate Files, Based On Size First, Then Md5 Hash, And Lists Them

$ find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate

List history, and find entries with "make"

$ history | grep make

Execute the history result list

$ !230

Execute previous command

$ !!

Record cmd history, file "typescript" will be created

$ script

$ ...

$ exit

List background jobs

$ jobs

Kill the background jobs

$ kill %25

Format command output as a nice table, "-s" specify separator

$ mount | column -t

or

$ cat /etc/passwd | column -t -s:

Check architecture, 32 bits or 64 bits

$ getconf LONG_BIT

Tar

$ tar zcf libstdc.tar libstdc*

Tar from file list

$ tar zcf archive.tar -T filelist.txt

or

$ tar zcf archive.tar `cat filelist.txt`

or

$ cat filelist.txt | xargs tar zcf archive.tar

Tar but exclude directory and folder

$ tar zcf libstdc.tar --exclude './data/*

$ tar zcf libstdc.tar --exclude './data

List tar file content

$ tar ztvf archive.tar

List zip content

$ less archive.tar

or

$ vim archive.tar

Zip to certain directory

$ tar zcf ~/temp/libstdc.tar libstdc*

Unzip from tar,tgz

$ tar zxf libstdc.tar.gz

or

$ tar zxf libstdc.tgz

Unzip from bz2, tbz, tb2

$ tar jxf libstdc.bz2

Unzip from zip

$ tar xvf libstdc.zip

Unzip to certain directory

$ tar zxf libstdc.tar -C ~/test/lib/

Encrypt file

$ gpg -c libstdc.zip

Decrypt file

$ gpg libstdc.zip.gpg

Split a big file into flies

$ split -b2m libstdc.zip.gpg libstdc_

Combine a big file from flies

$ cat libstdc_?? > libstdc.zip.gpg

Backup CD into iso format

# dd if=/dev/sr0 of=/home/shared/SUSE.iso

# mkdir /mnt/suse_iso

# mount -o loop /home/shared/SUSE.iso /mnt/suse_iso

# ls -al /mnt/suse_iso

Mount device

mount option SourceDevice TargetMountPoint

# mount -t ntfs /dev/hda /mnt/Data0

Mount External HDD, Format

mount option SourceDevice TargetMountPoint

# fdisk -l

# fdisk /dev/sdc

    m print help

    a add partition

    d delete partition

    w write to disk and save

    q quit without save

# mkfs -t ext2 /dev/sdc1

Copying file to host

scp SourceFile user@host:directory/TargetFile

# scp libstdc.tar root@10.1.2.124:/lib/

Copying file from host

scp user@host:directory/SourceFile TargetFile

# scp root@10.1.2.124:/lib/libstdc.tar /home/angkh/

Sync folder from A to B

sync option Source Target

# mount /dev/sdc1 /mnt/usbdrive

# rsync -ruv /home/shared/ /mnt/usbdrive/home/shared/

To check existing user, edit user full name

$ sudo less /etc/passwd

To check existing group

$ sudo less /etc/group

To limit user and machine logins through SSH

$ sudo vim /etc/ssh/sshd_config

AllowUsers bob@133.183.200.121 steve@133.183.200.132

To auto login SSH

Generate keypair at local PC

$ ssh-keygen -t rsa

This will generate

1) $HOME/.ssh/id_rsa        Private Key

2) $HOME/.ssh/id_rsa.pub    Public Key

Install (by append) your public key in the remote machine's authorized_keys:

cat ~/.ssh/id_rsa.pub | ssh username@xx.xx.xx.xx "cat >> ~/.ssh/authorized_keys"

To redirect output (both stdout=1, stderr=2) into file

$ make > log.txt 2>&1

To redirect output (both stdout=1, stderr=2) into file, and also output to screen

$ make 2>&1 | tee log.txt

To redirect output in csh/tcsh (both stdout=1, stderr=2) into file

$ make >& log.txt

Configure static IP

# vim /etc/network/interfaces

iface eth0 inet static

address 10.1.2.124

netmask 255.255.255.0

To obtain an ip address (manually after boot up)

# dhclient eth1

To obtain an ip address (auto upon boot up)

# vim /etc/network/interfaces

iface eth1 inet dhcp

To connect to ssid (manually after boot up)

# iwconfig eth1 essid "Jones"

# iwconfig eth1 key xxxx-xxxx-xx

To obtain an ip address (auto upon boot up)

# vim /etc/network/interfaces

auto eth1

iface eth1 inet dhcp

        pre-up iwconfig eth1 essid "Jones"

        pre-up iwconfig eth1 key xxxx-xxxx-xx

        dhclient eth1

Change owner of directory and files (recursively)

# chown -R angkh:angkh decodeRGB/

Customise bash shell prompt to full path

# vim ~/.bashrc

export PS1="[\u@\h \w]\$ "

Customise command alias

# vim ~/.bashrc

alias l="ls -alF --color"

Re-read .bash_profile after edit

$ source ~/.bashrc

Config vim as editor for visudo

$ sudo update-alternatives --config editor

Sudoer without need to type password (Format is "user machine=(effective-user) command")

# visudo

keanheong   ALL=(ALL) NOPASSWD:ALL

To change hostname

CentOS

# vim /etc/sysconfig/network

HOSTNAME=CentOS_192_168_1_12.localdomain

FreeBSD

# vim /etc/rc.conf

hostname="FreeBSD_192_168_1_12"

Change grub to read uuid instead of sda1 when boot up (portable HDD)

# blkid /dev/sda1

/dev/sda1: LABEL="/boot" UUID="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" TYPE="ext3"

# vim /etc/fstab

UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx    /boot    ext3    defaults    1 2

To delete MBR, bootloader (bs = the first 512 bytes of the harddrive to remove the bootloader)

# dd if=/dev/zero of=/dev/sdb bs=512 count=1

To search for package name

$ sudo apt-cache linux-kernel

To install gcc, make

$ sudo apt-get install build-essential

$ sudo yum groupinstall Development

To install linux header

$ sudo apt-get install linux-kernel-devel

To start automatically during the system startup

$ chkconfig smbd

$ chkconfig sshd

To view services that are configured to be started during system startup

$ chkconfig --list | grep 3:on

To padding with 0xFF existing file

$ dd if=/dev/zero ibs=1k count=131072 | tr "\000" "\377" > 128M.rom

or

$ tr "\000" "\377" < /dev/zero | dd ibs=1k count=131072 of=128M.rom

131072+0 records in

262144+0 records out

134217728 bytes transferred in 3.705787 secs (36218415 bytes/sec)

$ hexdump -C 128M.rom

00000000  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

*

07fffff0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

08000000

$ dd if=original.rom of=128M.rom conv=notrunc

$ hexdump -C 128M.rom

00000000  00 09 00 00 00 00 00 00  60 00 88 e7 60 08 c0 0f  |........`...`...|

00000010  15 70 00 5f 60 00 8b 77  60 08 c0 0f 15 70 00 5f  |.p._`..w`....p._|

00000020  60 00 a4 87 60 08 c0 0f  15 70 00 5f 60 00 aa 17  |`...`....p._`...|

00000030  60 08 c0 0f 15 70 00 5f  60 04 8b 27 60 08 c0 0f  |`....p._`..'`...|

00000040  15 70 00 5f 60 06 bc b7  60 08 c0 0f 15 70 00 5f  |.p._`...`....p._|

*

07fffff0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

08000000

Offset printed for each byte, left-aligned characters, 7 bytes per line

hexdump -v -e '7/1 "%5_ad:%-5_c" "\n"' test.txt

8 bytes per line

hexdump -v -e '8/2 "%4x," "\n"' test.bin > test.csv

8 bytes per line, signed decimal

hexdump -v -e '8/2 "%i," "\n"' test.bin > test.csv

16 bytes per line, unsigned decimal

hexdump -v -e '16/2 "%4u," "\n"' test.raw > test.csv

Reads one byte and prints it as hex number

/1 "%03x"

Reads one byte and prints it as signed decimal integer, repeats two times

2/1 " %03d"

Reads zero bytes and prints end of line

/0 "\n"

Bash shell loop to do for a file list

#!/bin/bash

for files in $(ls)

do

    echo $files

    echo ${files%.*}

    hexdump -v -e '16/2 "%4x," "\n"' $files > ${files%.*}.csv

done

Useful alias

alias l='ls -CF'

alias la='ls -A'

alias ll='ls -alF'

alias ls='ls --color=auto'

alias gb='git branch'

alias gc='git checkout'

alias gd='git diff'

alias glp='git log --pretty=format:"%h | %ci | %an | %s"'

alias gl='git log -20'

alias gpn='git pull --no-commit'

alias gs='git status'

alias gsu='git status -uno'

alias cd1="cd .."

alias cd2="cd ../.."

alias cd3="cd ../../.."

alias cd4="cd ../../../.."

alias cd5="cd ../../../../.."