Linex Command

	Comd Description # arch show architecture of machine(1)   # cal 2007 show the timetable of 2007   # cat /proc/cpuinfo show information CPU info   # cat /proc/interrupts show interrupts   # cat /proc/meminfo verify memory use   # cat /proc/swaps show file(s) swap   # cat /proc/version show version of the kernel   # cat /proc/net/dev show network adpters and statistics   # cat /proc/mounts show mounted file system(s)   # clock -w save date changes on BIOS   # date show system date   # date 041217002007.00 set date and time - MonthDayhoursMinutesYear.Seconds   # dmidecode -q show hardware system components - (SMBIOS / DMI)   # hdparm -i /dev/hda displays the characteristics of a hard-disk   # hdparm -tT /dev/sda perform test reading on a hard-disk   # lspci -tv display PCI devices   # lsusb -tv show USB devices   # uname -m show architecture of machine(2)   # uname -r show used kernel version
Comd			Description
# init 0			shutdown system(2)
# logout			leaving session
# reboot			reboot(2)
# shutdown -h now			shutdown system(1)
# shutdown -h 16:30 &			planned shutdown of the system
# shutdown -c			cancel a planned shutdown of the system
# shutdown -r now			reboot(1)
# telinit 0			shutdown system(3)
Comd			Description
# cd /home			enter to directory '/ home'
# cd ..			go back one level
# cd ../..			go back two levels
# cd			go to home directory
# cd ~user1			go to home directory
# cd -			go to previous directory
# cp file1 file2			copying a file
# cp dir/* .			copy all files of a directory within the current work directory
# cp -a /tmp/dir1 .			copy a directory within the current work directory
# cp -a dir1 dir2			copy a directory
# cp file file1			outputs the mime type of the file as text
# iconv -l			lists known encodings
# iconv -f fromEncoding -t toEncoding inputFile > outputFile			converting the coding of characters from one format to another
# find . -maxdepth 1 -name *.jpg -print -exec convert			batch resize files in the current directory and send them to a thumbnails directory (requires convert from Imagemagick)
# ln -s file1 lnk1			create a symbolic link to file or directory
# ln file1 lnk1			create a physical link to file or directory
# ls			view files of directory
# ls -F			view files of directory
# ls -l			show details of files and directory
# ls -a			show hidden files
# ls *0-9*			show files and directory containing numbers
# lstree			show files and directories in a tree starting from root(2)
# mkdir dir1			create a directory called 'dir1'
# mkdir dir1 dir2			create two directories simultaneously
# mkdir -p /tmp/dir1/dir2			create a directory tree
# mv dir1 new_dir			rename / move a file or directory
# pwd			show the path of work directory
# rm -f file1			delete file called 'file1'
# rm -rf dir1			remove a directory called 'dir1' and contents recursively
# rm -rf dir1 dir2			remove two directories and their contents recursively
# rmdir dir1			delete directory called 'dir1'
# touch -t 0712250000 file1			modify timestamp of a file or directory - (YYMMDDhhmm)
# tree			show files and directories in a tree starting from root(1)
Comd			Description
# find / -name file1			search file and directory into root filesystem from '/'
# find / -user user1			search files and directories belonging to 'user1'
# find /home/user1 -name \*.bin			search files with '. bin' extension within directory '/ home/user1'
# find /usr/bin -type f -atime +100			search binary files are not used in the last 100 days
# find /usr/bin -type f -mtime -10			search files created or changed within 10 days
# find / -name *.rpm -exec chmod 755 '{}' \;			search files with '.rpm' extension and modify permits
# find / -xdev -name \*.rpm			search files with '.rpm' extension ignoring removable partitions as cdrom, pen-drive, etc.…
# locate \*.ps			find files with the '.ps' extension - first run 'updatedb' comd
# whereis halt			show location of a binary file, source or
# which halt			show full path to a binary / executable
Comd			Description
# fuser -km /mnt/hda2			force umount when the device is busy
# mount /dev/hda2 /mnt/hda2			mount disk called hda2 - verify existence of the directory '/ mnt/hda2'
# mount /dev/fd0 /mnt/floppy			mount a floppy disk
# mount /dev/cdrom /mnt/cdrom			mount a cdrom / dvdrom
# mount /dev/hdc /mnt/cdrecorder			mount a cdrw / dvdrom
# mount /dev/hdb /mnt/cdrecorder			mount a cdrw / dvdrom
# mount -o loop file.iso /mnt/cdrom			mount a file or iso image
# mount -t vfat /dev/hda5 /mnt/hda5			mount a Windows FAT32 file system
# mount /dev/sda1 /mnt/usbdisk			mount a usb pen-drive or flash-drive
# mount -t smbfs -o username=user,password=pass //WinClient/share /mnt/share			mount a windows network share
# umount /dev/hda2			unmount disk called hda2 - exit from mount point '/ mnt/hda2' first
# umount -n /mnt/hda2			run umount without writing the file /etc/mtab - useful when the file is read-only or the hard disk is full
	Comd Description # df -h show list of partitions mounted   # dpkg-query -W -f='${Installed-Size;10}t${Package}n' | sort -k1,1n show the used space by installed deb packages, sorting by size (debian, ubuntu and alike)   # du -sh dir1 estimate space used by directory 'dir1'   # du -sk * | sort -rn show size of the files and directories sorted by size   # ls -lSr |more show size of the files and directories ordered by size   # rpm -q -a --qf '%10{SIZE}t%{NAME}n' | sort -k1,1n show space used by rpm packages installed sorted by size (fedora, redhat and like)
	Comd Description # chage -E 2005-12-31 user1 set deadline for user password   # groupadd group create a new group   # groupdel group delete a group   # groupmod -n moon sun rename a group from moon to sun   # grpck check correct syntax and file format of '/etc/group' and groups existence   # newgrp - group log into a new group to change default group of newly created files   # passwd change password   # passwd user1 change a user password (only by root)   # pwck check correct syntax and file format of '/etc/passwd' and users existence   # useradd -c "User Linux" -g admin -d /home/user1 -s /bin/bash user1 create a new user "user1" belongs "admin" group   # useradd user1 create a new user   # userdel -r user1 delete a user ( '-r' eliminates home directory)   # usermod -c "User FTP" -g system -d /ftp/user1 -s /bin/nologin user1 change user attributes
Comd			Description
# chgrp group1 file1			change group of files
# chmod ugo+rwx directory1			set permissions reading (r), write (w) and (x) access to users owner (u) group (g) and others (o)
# chmod go-rwx directory1			remove permits reading (r), write (w) and (x) access to users group (g) and others (or
# chmod u+s /bin/file1			set SUID bit on a binary file - the user that running that file gets same privileges as owner
# chmod u-s /bin/file1			disable SUID bit on a binary file
# chmod g+s /home/public			set SGID bit on a directory - similar to SUID but for directory
# chmod g-s /home/public			disable SGID bit on a directory
# chmod o+t /home/public			set STIKY bit on a directory - allows files deletion only to legitimate owners
# chmod o-t /home/public			disable STIKY bit on a directory
# chown user1 file1			change owner of a file
# chown -R user1 directory1			change user owner of a directory and all the files and directories contained inside
# chown user1:group1 file1			change user and group ownership of a file
# find / -perm -u+s			view all files on the system with SUID configured
# ls -lh			show permits on files
# ls /tmp | pr -T5 -W$COLUMNS			divide terminal into 5 columns
Comd			Description
# chattr +a file1			allows write opening of a file only append mode
# chattr +c file1			allows that a file is compressed / decompressed automatically by the kernel
# chattr +d file1			makes sure that the program ignores Dump the files during backup
# chattr +i file1			makes it an immutable file, which can not be removed, altered, renamed or linked
# chattr +s file1			allows a file to be deleted safely
# chattr +S file1			makes sure that if a file is modified changes are written in synchronous mode as with sync
# chattr +u file1			allows you to recover the contents of a file even if it is canceled
# lsattr			show specials attributes
Comd			Description
# bunzip2 file1.bz2			decompress a file called 'file1.bz2'
# bzip2 file1			compress a file called 'file1'
# gunzip file1.gz			decompress a file called 'file1.gz'
# gzip file1			compress a file called 'file1'
# gzip -9 file1			compress with maximum compression
# rar a file1.rar test_file			create an archive rar called 'file1.rar'
# rar a file1.rar file1 file2 dir1			compress 'file1', 'file2' and 'dir1' simultaneously
# rar x file1.rar			decompress rar archive
# tar -cvf archive.tar file1			create a uncompressed tarball
# tar -cvf archive.tar file1 file2 dir1			create an archive containing 'file1', 'file2' and 'dir1'
# tar -tf archive.tar			show contents of an archive
# tar -xvf archive.tar			extract a tarball
# tar -xvf archive.tar -C /tmp			extract a tarball into / tmp
# tar -cvfj archive.tar.bz2 dir1			create a tarball compressed into bzip2
# tar -xvfj archive.tar.bz2			decompress a compressed tar archive in bzip2
# tar -cvfz archive.tar.gz dir1			create a tarball compressed into gzip
# tar -xvfz archive.tar.gz			decompress a compressed tar archive in gzip
# unrar x file1.rar			decompress rar archive
# unzip file1.zip			decompress a zip archive
# zip file1.zip file1			create an archive compressed in zip
# zip -r file1.zip file1 file2 dir1			compress in zip several files and directories simultaneously
Comd Description # rpm -ivh package.rpm install a rpm package   # rpm -ivh --nodeeps package.rpm install a rpm package ignoring dependencies requests   # rpm -U package.rpm upgrade a rpm package without changing configuration files   # rpm -F package.rpm upgrade a rpm package only if it is already installed   # rpm -e package remove a rpm package   # rpm -qa show all rpm packages installed on the system   # rpm -qa | grep httpd show all rpm packages with the name "httpd"   # rpm -qi package obtain information on a specific package installed   # rpm -qg "System Environment/Daemons" show rpm packages of a group software   # rpm -ql package show list of files provided by a rpm package installed   # rpm -qc package show list of configuration files provided by a rpm package installed   # rpm -q package --whatrequires show list of dependencies required for a rpm packet   # rpm -q package --whatprovides show capability provided by a rpm package   # rpm -q package --scripts show scripts started during installation / removal   # rpm -q package --changelog show history of revisions of a rpm package   # rpm -qf /etc/httpd/conf/httpd.conf verify which rpm package belongs to a given file   # rpm -qp package.rpm -l show list of files provided by a rpm package not yet installed   # rpm --import /media/cdrom/RPM-GPG-KEY import public-key digital signature   # rpm --checksig package.rpm verify the integrity of a rpm package   # rpm -qa gpg-pubkey verify integrity of all rpm packages installed   # rpm -V package check file size, permissions, type, owner, group, MD5 checksum and last modification   # rpm -Va check all rpm packages installed on the system - use with caution   # rpm -Vp package.rpm verify a rpm package not yet installed   # rpm -ivh /usr/src/redhat/RPMS/`arch`/package.rpm install a package built from a rpm source   # rpm2cpio package.rpm | cpio --extract --make-directories *bin* extract executable file from a rpm package   # rpmbuild --rebuild package.src.rpm build a rpm package from a rpm source
Comd			Description
# yum -y install package			download and install a rpm package
# yum localinstall package.rpm			That will install an RPM, and try to resolve all the dependencies for you using your repositories.
# yum -y update			update all rpm packages installed on the system
# yum update package			upgrade a rpm package
# yum remove package			remove a rpm package
# yum list			list all packages installed on the system
# yum search package			find a package on rpm repository
# yum clean package			clean up rpm cache erasing downloaded packages
# yum clean headers			remove all files headers that the system uses to resolve dependency
# yum clean all			remove from the cache packages and headers files
Comd			Description
# dpkg -i package.deb			install / upgrade a deb package
# dpkg -r package			remove a deb package from the system
# dpkg -l			show all deb packages installed on the system
# dpkg -l | grep httpd			show all deb packages with the name "httpd"
# dpkg -s package			obtain information on a specific package installed on system
# dpkg -L package			show list of files provided by a package installed on system
# dpkg --contents package.deb			show list of files provided by a package not yet installed
# dpkg -S /bin/ping			verify which package belongs to a given file
Comd			Description
# apt-cache search package			returns list of packages which corresponds string "searched-packages"
# apt-cdrom install package			install / upgrade a deb package from cdrom
# apt-get install package			install / upgrade a deb package
# apt-get update			update the package list
# apt-get upgrade			upgrade all of the installed packages
# apt-get remove package			remove a deb package from system
# apt-get check			verify correct resolution of dependencies
# apt-get clean			clean up cache from packages downloaded
Comd			Description
# cat file1			view the contents of a file starting from the first row
# head -2 file1			view first two lines of a file
# less file1			similar to 'more' comd but which allows backward movement in the file as well as forward movement
# more file1			view content of a file along
# tac file1			view the contents of a file starting from the last line
# tail -2 file1			view last two lines of a file
# tail -f /var/log/messages			view in real time what is added to a file
Comd			Description
# cat example.txt | awk 'NR%2==1'			remove all even lines from example.txt
# echo a b c | awk '{print $1}'			view the first column of a line
# echo a b c | awk '{print $1,$3}'			view the first and third column of a line
# cat -n file1			number row of a file
# comm -1 file1 file2			compare contents of two files by deleting only unique lines from 'file1'
# comm -2 file1 file2			compare contents of two files by deleting only unique lines from 'file2'
# comm -3 file1 file2			compare contents of two files by deleting only the lines that appear on both files
# diff file1 file2			find differences between two files
# grep Aug /var/log/messages			look up words "Aug" on file '/var/log/messages'
# grep ^Aug /var/log/messages			look up words that begin with "Aug" on file '/var/log/messages'
# grep 0-9 /var/log/messages			select from file '/var/log/messages' all lines that contain numbers
# grep Aug -R /var/log/*			search string "Aug" at directory '/var/log' and below
# paste file1 file2			merging contents of two files for columns
# paste -d '+' file1 file2			merging contents of two files for columns with '+' delimiter on the center
# sdiff file1 file2			find differences between two files and merge interactively alike "diff"
# sed 's/string1/string2/g' example.txt			replace "string1" with "string2" in example.txt
# sed '/^$/d' example.txt			remove all blank lines from example.txt
# sed '/ *#/d; /^$/d' example.txt			remove comments and blank lines from example.txt
# sed -e '1d' exampe.txt			eliminates the first line from file example.txt
# sed -n '/string1/p'			view only lines that contain the word "string1"
# sed -e 's/ *$//' example.txt			remove empty characters at the end of each row
# sed -e 's/string1//g' example.txt			remove only the word "string1" from text and leave intact all
# sed -n '1,5p' example.txt			print from 1th to 5th row of example.txt
# sed -n '5p;5q' example.txt			print row number 5 of example.txt
# sed -e 's/00*/0/g' example.txt			replace more zeros with a single zero
# sort file1 file2			sort contents of two files
# sort file1 file2 | uniq			sort contents of two files omitting lines repeated
# sort file1 file2 | uniq -u			sort contents of two files by viewing only unique line
# sort file1 file2 | uniq -d			sort contents of two files by viewing only duplicate line
# echo 'word' | tr ':lower:' ':upper:'			convert from lower case in upper case
Comd			Description
# dos2unix filedos.txt fileunix.txt			convert a text file format from MSDOS to UNIX
# recode ..HTML < page.txt > page.html			convert a text file to html
# recode -l | more			show all available formats conversion
# unix2dos fileunix.txt filedos.txt			convert a text file format from UNIX to MSDOS
Comd			Description
# badblocks -v /dev/hda1			check bad blocks on disk hda1
# dosfsck /dev/hda1			repair / check integrity of dos filesystems on disk hda1
# e2fsck /dev/hda1			repair / check integrity of ext2 filesystem on disk hda1
# e2fsck -j /dev/hda1			repair / check integrity of ext3 filesystem on disk hda1
# fsck /dev/hda1			repair / check integrity of linux filesystem on disk hda1
# fsck.ext2 /dev/hda1			repair / check integrity of ext2 filesystem on disk hda1
# fsck.ext3 /dev/hda1			repair / check integrity of ext3 filesystem on disk hda1
# fsck.vfat /dev/hda1			repair / check integrity of fat filesystem on disk hda1
# fsck.msdos /dev/hda1			repair / check integrity of dos filesystem on disk hda1
Comd			Description
# fdformat -n /dev/fd0			format a floppy disk
# mke2fs /dev/hda1			create a filesystem type linux ext2 on hda1 partition
# mke2fs -j /dev/hda1			create a filesystem type linux ext3 (journal) on hda1 partition
# mkfs /dev/hda1			create a filesystem type linux on hda1 partition
# mkfs -t vfat 32 -F /dev/hda1			create a FAT32 filesystem
# mkswap /dev/hda3			create a swap filesystem
Comd			Description
# mkswap /dev/hda3			create a swap filesystem
# swapon /dev/hda3			activating a new swap partition
# swapon /dev/hda2 /dev/hdb3			activate two swap partitions
Comd			Description
# find /var/log -name '*.log' | tar cv --files-from=- | bzip2 > log.tar.bz2			find all files with '.log' extention and make an bzip archive
# find /home/user1 -name '*.txt' | xargs cp -av --target-directory=/home/backup/ --parents			find and copy all files with '.txt' extention from a directory to another
# dd bs=1M if=/dev/hda | gzip | ssh user@ip_addr 'dd of=hda.gz'			make a backup of a local hard disk on remote host via ssh
# dd if=/dev/sda of=/tmp/file1			backup content of the harddrive to a file
# dd if=/dev/hda of=/dev/fd0 bs=512 count=1			make a copy of MBR (Master Boot Record) to floppy
# dd if=/dev/fd0 of=/dev/hda bs=512 count=1			restore MBR from backup copy saved to floppy
# dump -0aj -f /tmp/home0.bak /home			make a full backup of directory '/home'
# dump -1aj -f /tmp/home0.bak /home			make a incremental backup of directory '/home'
# restore -if /tmp/home0.bak			restoring a backup interactively
# rsync -rogpav --delete /home /tmp			synchronization between directories
# rsync -rogpav -e ssh --delete /home ip_address:/tmp			rsync via SSH tunnel
# rsync -az -e ssh --delete ip_addr:/home/public /home/local			synchronize a local directory with a remote directory via ssh and compression
# rsync -az -e ssh --delete /home/local ip_addr:/home/public			synchronize a remote directory with a local directory via ssh and compression
# tar -Puf backup.tar /home/user			make a incremental backup of directory '/home/user'
# ( cd /tmp/local/ && tar c . ) | ssh -C user@ip_addr 'cd /home/share/ && tar x -p'			copy content of a directory on remote directory via ssh
# ( tar c /home ) | ssh -C user@ip_addr 'cd /home/backup-home && tar x -p'			copy a local directory on remote directory via ssh
# tar cf - . | (cd /tmp/backup ; tar xf - )			local copy preserving permits and links from a directory to another
Comd			Description
# cd-paranoia -B			rip audio tracks from a CD to wav files
# cd-paranoia --			rip first three audio tracks from a CD to wav files
# cdrecord -v gracetime=2 dev=/dev/cdrom -eject blank=fast -force			clean a rewritable cdrom
# cdrecord -v dev=/dev/cdrom cd.iso			burn an ISO image
# gzip -dc cd_iso.gz | cdrecord dev=/dev/cdrom -			burn a compressed ISO image
# cdrecord --scanbus			scan bus to identify the channel scsi
# dd if=/dev/hdc | md5sum			perform an md5sum on a device, like a CD
# mkisofs /dev/cdrom > cd.iso			create an iso image of cdrom on disk
# mkisofs /dev/cdrom | gzip > cd_iso.gz			create a compressed iso image of cdrom on disk
# mkisofs -J -allow-leading-dots -R -V			create an iso image of a directory
# mount -o loop cd.iso /mnt/iso			mount an ISO image
Comd			Description
# dhclient eth0			active interface 'eth0' in dhcp mode
# ethtool eth0			show network statistics of eth0
# host www.example.com			lookup hostname to resolve name to ip address and viceversa
# hostname			show hostname of system
# ifconfig eth0			show configuration of an ethernet network card
# ifconfig eth0 192.168.1.1 netmask 255.255.255.0			configure IP Address
# ifconfig eth0 promisc			configure 'eth0' in promiscuous mode to gather packets (sniffing)
# ifdown eth0			disable an interface 'eth0'
# ifup eth0			activate an interface 'eth0'
# ip link show			show link status of all network interfaces
# iwconfig eth1			show wireless networks
# iwlist scan			wifi scanning to display the wireless connections available
# mii-tool eth0			show link status of 'eth0'
# netstat -tup			show all active network connections and their PID
# netstat -tupl			show all network services listening on the system and their PID
# netstat -rn			show routing table alike "route -n"
# nslookup www.example.com			lookup hostname to resolve name to ip address and viceversa
# route -n			show routing table
# route add -net 0/0 gw IP_Gateway			configure default gateway
# route add -net 192.168.0.0 netmask 255.255.0.0 gw 192.168.1.1			configure static route to reach network '192.168.0.0/16'
# route del 0/0 gw IP_gateway			remove static route
# echo "1" > /proc/sys/net/ipv4/ip_forward			activate ip routing
# tcpdump tcp port 80			show all HTTP traffic
# whois www.example.com			lookup on Whois database
Comd			Description
# mount -t smbfs -o username=user,password=pass //WinClient/share /mnt/share			mount a windows network share
# nbtscan ip_addr			netbios name resolution
# nmblookup -A ip_addr			netbios name resolution
# smbclient -L ip_addr/hostname			show remote shares of a windows host
# smbget -Rr smb://ip_addr/share			like wget can download files from a host windows via smb
Comd			Description
# iptables -t filter -L			show all chains of filtering table
# iptables -t nat -L			show all chains of nat table
# iptables -t filter -F			clear all rules from filtering table
# iptables -t nat -F			clear all rules from table nat
# iptables -t filter -X			delete any chains created by user
# iptables -t filter -A INPUT -p tcp --dport telnet -j ACCEPT			allow telnet connections to input
# iptables -t filter -A OUTPUT -p tcp --dport http -j DROP			block HTTP connections to output
# iptables -t filter -A FORWARD -p tcp --dport pop3 -j ACCEPT			allow POP3 connections to forward chain
# iptables -t filter -A INPUT -j LOG --log-prefix			Logging on input chain
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE			configure a PAT (Port Address Traslation) on eth0 masking outbound packets
# iptables -t nat -A PREROUTING -d 192.168.0.1 -p tcp -m tcp --dport 22 -j DNAT --to-destination 10.0.0.2:22			redirect packets addressed to a host to another host
Comd			Description
# free -m			displays status of RAM in megabytes
# kill -9 process_id			force closure of the process and finish it
# kill -1 process_id			force a process to reload configuration
# last reboot			show history reboot
# lsmod			display kernel loaded
# lsof -p process_id			display a list of files opened by processes
# lsof /home/user1			displays a list of open files in a given path system
# ps -eafw			displays linux tasks
# ps -e -o pid,args --forest			displays linux tasks in a hierarchical mode
# pstree			Shows a tree system processes
# smartctl -A /dev/hda			monitoring reliability of a hard-disk through SMART
Comd			Description
# alias hh='history'			set an alias for a comd - hh = history
# apropos ...keyword			display a list of comds that pertain to keywords of a program , useful when you know what your program does, but you don't know the name of the comd
# chsh			change shell comd
# chsh --list-shells			nice comd to know if you have to remote into another box
# gpg -c file1			encrypt a file with GNU Privacy Guard
# gpg file1.gpg			decrypt a file with GNU Privacy Guard
# ldd /usr/bin/ssh			show shared libraries required by ssh program
#  ping			display the on-line ual pages for example on ping comd - use '-k' option to find any related comds
# mkbootdisk --device /dev/fd0 `uname -r`			create a boot floppy
# wget -r www.example.com			download an entire web site
# wget -c www.example.com/file.iso			download a file with the ability to stop the download and resume later
# echo 'wget -c www.example.com/files.iso' | at 09:00			start a download at any given time
# whatis ...keyword			displays description of what a program does
# who -a			show who is logged on, and print: time of last system boot, dead processes, system login processes, active processes spawned by init, current runlevel, last system clock change
Comd			Description
# pac -S name			Install package 'name' with dependencies
# pac -R name			Delete package 'name' and all files of it