All command and swap partition create

Command	Description
# rpm -ivh [package.rpm]	install a rpm package [man]
# rpm -ivh --nodeeps [package.rpm]	install a rpm package ignoring dependencies requests [man]
# rpm -U [package.rpm]	upgrade a rpm package without changing configuration files [man]
# rpm -F [package.rpm]	upgrade a rpm package only if it is already installed [man]
# rpm -e [package]	remove a rpm package [man]
# rpm -qa	show all rpm packages installed on the system [man]
# rpm -qa | grep httpd	show all rpm packages with the name "httpd" [man]
# rpm -qi [package]	obtain information on a specific package installed [man]
# rpm -qg "System Environment/Daemons"	show rpm packages of a group software [man]
# rpm -ql [package]	show list of files provided by a rpm package installed [man]
# rpm -qc [package]	show list of configuration files provided by a rpm package installed [man]
# rpm -q [package] --whatrequires	show list of dependencies required for a rpm packet [man]
# rpm -q [package] --whatprovides	show capability provided by a rpm package [man]
# rpm -q [package] --scripts	show scripts started during installation / removal [man]
# rpm -q [package] --changelog	show history of revisions of a rpm package [man]
# rpm -qf /etc/httpd/conf/httpd.conf	verify which rpm package belongs to a given file [man]
# rpm -qp [package.rpm] -l	show list of files provided by a rpm package not yet installed [man]
# rpm --import /media/cdrom/RPM-GPG-KEY	import public-key digital signature [man]
# rpm --checksig [package.rpm]	verify the integrity of a rpm package [man]
# rpm -qa gpg-pubkey	verify integrity of all rpm packages installed [man]
# rpm -V [package]	check file size, permissions, type, owner, group, MD5 checksum and last modification [man]
# rpm -Va	check all rpm packages installed on the system - use with caution [man]
# rpm -Vp [package.rpm]	verify a rpm package not yet installed [man]
# rpm -ivh /usr/src/redhat/RPMS/`arch`/[package.rpm]	install a package built from a rpm source [man]
# rpm2cpio [package.rpm] | cpio --extract --make-directories *bin*	extract executable file from a rpm package [man]
# rpmbuild --rebuild [package.src.rpm]	build a rpm package from a rpm source [man]

Command Description # yum -y install [package] download and install a rpm package [man] # yum localinstall [package.rpm] That will install an RPM, and try to resolve all the dependencies for you using your repositories. [man] # yum -y update update all rpm packages installed on the system [man] # yum update [package] upgrade a rpm package [man] # yum remove [package] remove a rpm package [man] # yum list list all packages installed on the system [man] # yum search [package] find a package on rpm repository [man] # yum clean [package] clean up rpm cache erasing downloaded packages [man] # yum clean headers remove all files headers that the system uses to resolve dependency [man] # yum clean all remove from the cache packages and headers files [man]

# dpkg -i [package.deb]	install / upgrade a deb package [man]
# dpkg -r [package]	remove a deb package from the system [man]
# dpkg -l	show all deb packages installed on the system [man]
# dpkg -l | grep httpd	show all deb packages with the name "httpd" [man]
# dpkg -s [package]	obtain information on a specific package installed on system [man]
# dpkg -L [package]	show list of files provided by a package installed on system [man]
# dpkg --contents [package.deb]	show list of files provided by a package not yet installed [man]
# dpkg -S /bin/ping	verify which package belongs to a given file [man]

# apt-cache search [package] returns list of packages which corresponds string "searched-packages" [man] # apt-cdrom install [package] install / upgrade a deb package from cdrom [man] # apt-get install [package] install / upgrade a deb package [man] # apt-get update update the package list [man] # apt-get upgrade upgrade all of the installed packages [man] # apt-get remove [package] remove a deb package from system [man] # apt-get check verify correct resolution of dependencies [man] # apt-get clean clean up cache from packages downloaded [man]

# cat file1	view the contents of a file starting from the first row [man]
# head -2 file1	view first two lines of a file [man]
# less file1	similar to 'more' command but which allows backward movement in the file as well as forward movement [man]
# more file1	view content of a file along [man]
# tac file1	view the contents of a file starting from the last line [man]
# tail -2 file1	view last two lines of a file [man]
# tail -f /var/log/messages	view in real time what is added to a file [man]

# cat example.txt | awk 'NR%2==1'	remove all even lines from example.txt [man]
# echo a b c | awk '{print $1}'	view the first column of a line [man]
# echo a b c | awk '{print $1,$3}'	view the first and third column of a line [man]
# cat -n file1	number row of a file [man]
# comm -1 file1 file2	compare contents of two files by deleting only unique lines from 'file1' [man]
# comm -2 file1 file2	compare contents of two files by deleting only unique lines from 'file2' [man]
# comm -3 file1 file2	compare contents of two files by deleting only the lines that appear on both files [man]
# diff file1 file2	find differences between two files [man]
# grep Aug /var/log/messages	look up words "Aug" on file '/var/log/messages' [man]
# grep ^Aug /var/log/messages	look up words that begin with "Aug" on file '/var/log/messages' [man]
# grep [0-9] /var/log/messages	select from file '/var/log/messages' all lines that contain numbers [man]
# grep Aug -R /var/log/*	search string "Aug" at directory '/var/log' and below [man]
# paste file1 file2	merging contents of two files for columns [man]
# paste -d '+' file1 file2	merging contents of two files for columns with '+' delimiter on the center [man]
# sdiff file1 file2	find differences between two files and merge interactively alike "diff" [man]
# sed 's/string1/string2/g' example.txt	replace "string1" with "string2" in example.txt [man]
# sed '/^$/d' example.txt	remove all blank lines from example.txt [man]
# sed '/ *#/d; /^$/d' example.txt	remove comments and blank lines from example.txt [man]
# sed -e '1d' exampe.txt	eliminates the first line from file example.txt [man]
# sed -n '/string1/p'	view only lines that contain the word "string1" [man]
# sed -e 's/ *$//' example.txt	remove empty characters at the end of each row [man]
# sed -e 's/string1//g' example.txt	remove only the word "string1" from text and leave intact all [man]
# sed -n '1,5p' example.txt	print from 1th to 5th row of example.txt [man]
# sed -n '5p;5q' example.txt	print row number 5 of example.txt [man]
# sed -e 's/00*/0/g' example.txt	replace more zeros with a single zero [man]
# sort file1 file2	sort contents of two files [man]
# sort file1 file2 | uniq
	sort contents of two files omitting lines repeated [man]
# sort file1 file2 | uniq -u
# sort file1 file2 | uniq -d	sort contents of two files by viewing only unique line [man]
# echo 'word' | tr '[:lower:]' '[:upper:]'	sort contents of two files by viewing only duplicate line [man]
	convert from lower case in upper case [man]

# dos2unix filedos.txt fileunix.txt	convert a text file format from MSDOS to UNIX [man]
# recode ..HTML < page.txt > page.html	convert a text file to html [man]
# recode -l | more	show all available formats conversion [man]
# unix2dos fileunix.txt filedos.txt	convert a text file format from UNIX to MSDOS [man]

# badblocks -v /dev/hda1	check bad blocks on disk hda1 [man]
# dosfsck /dev/hda1	repair / check integrity of dos filesystems on disk hda1 [man]
# e2fsck /dev/hda1	repair / check integrity of ext2 filesystem on disk hda1 [man]
# e2fsck -j /dev/hda1	repair / check integrity of ext3 filesystem on disk hda1 [man]
# fsck /dev/hda1	repair / check integrity of linux filesystem on disk hda1 [man]
# fsck.ext2 /dev/hda1	repair / check integrity of ext2 filesystem on disk hda1 [man]
# fsck.ext3 /dev/hda1	repair / check integrity of ext3 filesystem on disk hda1 [man]
# fsck.vfat /dev/hda1	repair / check integrity of fat filesystem on disk hda1 [man]
# fsck.msdos /dev/hda1	repair / check integrity of dos filesystem on disk hda1 [man]

# fdformat -n /dev/fd0	format a floppy disk [man]
# mke2fs /dev/hda1	create a filesystem type linux ext2 on hda1 partition [man]
# mke2fs -j /dev/hda1	create a filesystem type linux ext3 (journal) on hda1 partition [man]
# mkfs /dev/hda1	create a filesystem type linux on hda1 partition [man]
# mkfs -t vfat 32 -F /dev/hda1	create a FAT32 filesystem [man]
# mkswap /dev/hda3	create a swap filesystem [man]

# mkswap /dev/hda3	create a swap filesystem [man]
# swapon /dev/hda3	activating a new swap partition [man]
# swapon /dev/hda2 /dev/hdb3	activate two swap partitions [man]

# find /var/log -name '*.log' | tar cv --files-from=- | bzip2 > log.tar.bz2	find all files with '.log' extention and make an bzip archive [man]
# 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 [man]
# 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 [man]
# dd if=/dev/sda of=/tmp/file1	backup content of the harddrive to a file [man]
# dd if=/dev/hda of=/dev/fd0 bs=512 count=1	make a copy of MBR (Master Boot Record) to floppy [man]
# dd if=/dev/fd0 of=/dev/hda bs=512 count=1	restore MBR from backup copy saved to floppy [man]
# dump -0aj -f /tmp/home0.bak /home	make a full backup of directory '/home' [man]
# dump -1aj -f /tmp/home0.bak /home	make a incremental backup of directory '/home' [man]
# restore -if /tmp/home0.bak	restoring a backup interactively [man]
# rsync -rogpav --delete /home /tmp	synchronization between directories [man]
# rsync -rogpav -e ssh --delete /home ip_address:/tmp	rsync via SSH tunnel [man]
# rsync -az -e ssh --delete ip_addr:/home/public /home/local	synchronize a local directory with a remote directory via ssh and compression [man]
# rsync -az -e ssh --delete /home/local ip_addr:/home/public	synchronize a remote directory with a local directory via ssh and compression [man]
# tar -Puf backup.tar /home/user	make a incremental backup of directory '/home/user' [man]
# ( 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 [man]
# ( tar c /home ) | ssh -C user@ip_addr 'cd /home/backup-home && tar x -p'	copy a local directory on remote directory via ssh [man]
# tar cf - . | (cd /tmp/backup ; tar xf - )	local copy preserving permits and links from a directory to another [man]

# cd-paranoia -B	rip audio tracks from a CD to wav files [man]
# cd-paranoia --	rip first three audio tracks from a CD to wav files [man]
# cdrecord -v gracetime=2 dev=/dev/cdrom -eject blank=fast -force	clean a rewritable cdrom [man]
# cdrecord -v dev=/dev/cdrom cd.iso	burn an ISO image [man]
# gzip -dc cd_iso.gz | cdrecord dev=/dev/cdrom -	burn a compressed ISO image [man]
# cdrecord --scanbus	scan bus to identify the channel scsi [man]
# dd if=/dev/hdc | md5sum	perform an md5sum on a device, like a CD [man]
# mkisofs /dev/cdrom > cd.iso	create an iso image of cdrom on disk [man]
# mkisofs /dev/cdrom | gzip > cd_iso.gz	create a compressed iso image of cdrom on disk [man]
# mkisofs -J -allow-leading-dots -R -V	create an iso image of a directory [man]
# mount -o loop cd.iso /mnt/iso	mount an ISO image [man]

# dhclient eth0	active interface 'eth0' in dhcp mode [man]
# ethtool eth0	show network statistics of eth0 [man]
# host www.example.com	lookup hostname to resolve name to ip address and viceversa [man]
# hostname	show hostname of system [man]
# ifconfig eth0	show configuration of an ethernet network card [man]
# ifconfig eth0 192.168.1.1 netmask 255.255.255.0	configure IP Address [man]
# ifconfig eth0 promisc	configure 'eth0' in promiscuous mode to gather packets (sniffing) [man]
# ifdown eth0	disable an interface 'eth0' [man]
# ifup eth0	activate an interface 'eth0' [man]
# ip link show	show link status of all network interfaces [man]
# iwconfig eth1	show wireless networks [man]
# iwlist scan	wifi scanning to display the wireless connections available [man]
# mii-tool eth0	show link status of 'eth0' [man]
# netstat -tup	show all active network connections and their PID [man]
# netstat -tupl	show all network services listening on the system and their PID [man]
# netstat -rn	show routing table alike "route -n" [man]
# nslookup www.example.com	lookup hostname to resolve name to ip address and viceversa [man]
# route -n	show routing table [man]
# route add -net 0/0 gw IP_Gateway	configure default gateway [man]
# 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' [man]
# route del 0/0 gw IP_gateway	remove static route [man]
# echo "1" > /proc/sys/net/ipv4/ip_forward	activate ip routing [man]
# tcpdump tcp port 80	show all HTTP traffic [man]
# whois www.example.com	lookup on Whois database [man]

# mount -t smbfs -o username=user,password=pass //WinClient/share /mnt/share	mount a windows network share [man]
# nbtscan ip_addr	netbios name resolution [man]
# nmblookup -A ip_addr	netbios name resolution [man]
# smbclient -L ip_addr/hostname	show remote shares of a windows host [man]
# smbget -Rr smb://ip_addr/share	like wget can download files from a host windows via smb [man]

# iptables -t filter -L	show all chains of filtering table [man]
# iptables -t nat -L	show all chains of nat table [man]
# iptables -t filter -F	clear all rules from filtering table [man]
# iptables -t nat -F	clear all rules from table nat [man]
# iptables -t filter -X	delete any chains created by user [man]
# iptables -t filter -A INPUT -p tcp --dport telnet -j ACCEPT	allow telnet connections to input [man]
# iptables -t filter -A OUTPUT -p tcp --dport http -j DROP	block HTTP connections to output [man]
# iptables -t filter -A FORWARD -p tcp --dport pop3 -j ACCEPT	allow POP3 connections to forward chain [man]
# iptables -t filter -A INPUT -j LOG --log-prefix	Logging on input chain [man]
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE	configure a PAT (Port Address Traslation) on eth0 masking outbound packets [man]
# 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 [man]

# free -m displays status of RAM in megabytes [man] # kill -9 process_id force closure of the process and finish it [man] # kill -1 process_id force a process to reload configuration [man] # last reboot show history reboot [man] # lsmod display kernel loaded [man] # lsof -p process_id display a list of files opened by processes [man] # lsof /home/user1 displays a list of open files in a given path system [man] # ps -eafw displays linux tasks [man] # ps -e -o pid,args --forest displays linux tasks in a hierarchical mode [man] # pstree Shows a tree system processes [man] # smartctl -A /dev/hda monitoring reliability of a hard-disk through SMART [man] # smartctl -i /dev/hda check if SMART is active on a hard-disk [man] # strace -c ls >/dev/null display system calls made and received by a process [man] # strace -f -e open ls >/dev/null display library calls [man] # tail /var/log/dmesg show events inherent to the process of booting kernel [man] # tail /var/log/messages show system events [man] # top display linux tasks using most cpu [man] # watch -n1 'cat /proc/interrupts' display interrupts in real-time [man]

# alias hh='history'	set an alias for a command - hh = history [man]
# apropos ...keyword	display a list of commands that pertain to keywords of a program , useful when you know what your program does, but you don't know the name of the command [man]
# chsh	change shell command [man]
# chsh --list-shells	nice command to know if you have to remote into another box [man]
# gpg -c file1	encrypt a file with GNU Privacy Guard [man]
# gpg file1.gpg	decrypt a file with GNU Privacy Guard [man]
# ldd /usr/bin/ssh	show shared libraries required by ssh program [man]
# man ping	display the on-line manual pages for example on ping command - use '-k' option to find any related commands [man]
# mkbootdisk --device /dev/fd0 `uname -r`	create a boot floppy [man]
# wget -r www.example.com	download an entire web site [man]
# wget -c www.example.com/file.iso	download a file with the ability to stop the download and resume later [man]
# echo 'wget -c www.example.com/files.iso' | at 09:00	start a download at any given time [man]
# whatis ...keyword	displays description of what a program does [man]
# 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 [man]

# pacman -S name	Install package 'name' with dependencies [man]
# pacman -R name	Delete package 'name' and all files of it [man]

Syntax	Description	Example(s)
rpm -ivh {rpm-file}	Install the package	rpm -ivh mozilla-mail-1.7.5-17.i586.rpm rpm -ivh --test mozilla-mail-1.7.5-17.i586.rpm
rpm -Uvh {rpm-file}	Upgrade package	rpm -Uvh mozilla-mail-1.7.6-12.i586.rpm rpm -Uvh --test mozilla-mail-1.7.6-12.i586.rpm
rpm -ev {package}	Erase/remove/ an installed package	rpm -ev mozilla-mail
rpm -ev --nodeps {package}	Erase/remove/ an installed package without checking for dependencies	rpm -ev --nodeps mozilla-mail
rpm -qa	Display list all installed packages	rpm -qa rpm -qa | less
rpm -qi {package}	Display installed information along with package version and short description	rpm -qi mozilla-mail
rpm -qf {/path/to/file}	Find out what package a file belongs to i.e. find what package owns the file	rpm -qf /etc/passwd rpm -qf /bin/bash
rpm -qc {pacakge-name}	Display list of configuration file(s) for a package	rpm -qc httpd
rpm -qcf {/path/to/file}	Display list of configuration files for a command	rpm -qcf /usr/X11R6/bin/xeyes
rpm -qa --last	Display list of all recently installed RPMs	rpm -qa --last rpm -qa --last | less
rpm -qpR {.rpm-file} rpm -qR {package}	Find out what dependencies a rpm file has	rpm -qpR mediawiki-1.4rc1-4.i586.rpm rpm -qR bash

Linux Add a Swap File – Howto

by NIXCRAFT on MAY 18, 2006 · 34 COMMENTS· last updated at JANUARY 4, 2012

Ineed additional swap space to improve my system performance. How do I add a swap file to Linux system using command line options?

In Linux, as in most other Unix-like operating systems, it is common to use a whole partition of a hard disk for swapping. However, with the 2.6 Linux kernel, swap files are just as fast as swap partitions, although I recommends using a swap partition. The administrative flexibility of swap files outweighs that of partitions; since modern high capacity hard drives can remap physical sectors, no partition is guaranteed to be contiguous. You can add swap file as a dedicated partition or use following instructions to create a swap file.

Procedure To Add a Swap File Under Linux

You need to use the dd command to create swap file. The mkswap command is used to set up a Linux swap area on a device or in a file.

Step #1: Login as the Root User

Open a terminal window (select Applications > Accessories > Terminal) or login to remote server using the ssh client. Switch to the root user by typing su - and entering the root password, when prompted

Step #2: Create Storage File

Type the following command to create 512MB swap file (1024 * 512MB = 524288 block size):# dd if=/dev/zero of=/swapfile1 bs=1024 count=524288
Where,

1. if=/dev/zero : Read from /dev/zero file. /dev/zero is a special file in that provides as many null characters to build storage file called /swapfile1.
2. of=/swapfile1 : Read from /dev/zero write stoage file to /swapfile1.
3. bs=1024 : Read and write 1024 BYTES bytes at a time.
4. count=524288 : Copy only 523288 BLOCKS input blocks.

Step #3: Set Up a Linux Swap Area

Type the following command to set up a Linux swap area in a file:# mkswap /swapfile1
Setup correct file permission for security reasons, enter:# chown root:root /swapfile1
# chmod 0600 /swapfile1
A world-readable swap file is a huge local vulnerability. The above command make sure only root user can read/write to the file. Finally, activate /swapfile1 swap space immediately, enter:# swapon /swapfile1

To activate /swapfile1 after Linux system reboot, add entry to /etc/fstab file. Open this file using a text editor such as vi:# vi /etc/fstab

Append the following line:/swapfile1 swap swap defaults 0 0
Save and close the file. Next time Linux comes up after reboot, it enables the new swap file for you automatically.

How do I Verify Swap is Activated or Not?

Simply use the free command:$ free -m