{"id":703,"date":"2012-07-13T15:39:14","date_gmt":"2012-07-13T07:39:14","guid":{"rendered":"http:\/\/rmohan.com\/?p=703"},"modified":"2012-07-27T07:41:33","modified_gmt":"2012-07-26T23:41:33","slug":"linux-commands","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=703","title":{"rendered":"Linux Commands"},"content":{"rendered":"
To view System Resource Information<\/strong><\/div>\n
uname –help
\nuname -r
\ngrep model \/proc\/cpuinfo
\ngrep MemFree \/proc\/meminfo
\nsudo -u root lastcomm -f \/var\/account\/pacct
\ncat \/proc\/version
\n# cat \/proc\/cpuinfo
\n# cat \/proc\/meminfo
\n# cat \/proc\/zoneinfo
\n# cat \/proc\/mounts
\ncat \/etc\/redhat-release
\ngrep MemTotal \/proc\/meminfo
\ngrep SwapTotal \/proc\/meminfo
\ndf -k \/tmp
\ngrep “model name” \/proc\/cpuinfo
\nifconfig (\/sbin\/ifconfig)
\nuaname -r
\nlshal:detected hardware
\nrpm -qa:\u00a0 display pakage
\nrpm -qa | less
\nLinux Kernel Information:<\/strong><\/div>\n
cat \/etc\/sysctl.conf
\ncat \/etc\/hosts
\n\/sbin\/ifconfig
\nUname -r
\ncat \/etc\/security\/limits.conf
\ncat \/proc\/sys\/kernel\/sem
\ncat \/proc\/sys\/kernel\/shmmax
\ncat \/proc\/sys\/kernel\/shmall
\ncat \/proc\/sys\/kernel\/shmmni
\ncat \/proc\/sys\/fs\/file-max
\ncat \/proc\/sys\/net\/ipv4\/ip_local_port_range
\n\/sbin\/lsmod
\ncat \/etc\/issue
\nsysctl -a | grep shm
\nsysctl -a | grep ip_local_port_range
\n\/etc\/inittab:\u00a0 init process determines which runlevel it should be
\nw, ps -a, ps -Alf, ps -AlFH, ps -AlLm
\nps -u oracle, ps -u anguyen<\/div>\n
Commands to monitor bottlenecks such as Disk, Memory \/ CPU\/Network, or System Activity:<\/strong><\/div>\n
top ? t, m, A: top consumer, r: renice, o: interactively select
\nvmstat 3, vmstat -m:memority slab info, vmstat -a
\nw, ps -a, ps -Alf, ps -AlFH, ps -AlLm
\nps -u oracle, ps -u attunity
\nuptime
\nfree
\nfee -s 2
\nwatch -n 3 -d free
\nwatch -d cat \/proc\/meminfo
\nsar -B -f \/var\/log\/sa\/sa14
\nsar -W -f \/var\/log\/sa\/sa14
\nvmstat -m
\nvmstat -a
\nipcs -sm
\nipcs -lms
\nsar -n DEV | more
\nsar 4 5
\nmpstat -P ALL
\nMEMORY intensive process:<\/strong><\/div>\n
ps -e -o pmem,pid,user,tty,args | grep -i oracle | sort -n -k 1 -r | head
\nwatch -n 3 -d free
\nwatch -d cat \/proc\/meminfo
\nCPU intensive process<\/strong><\/div>\n
top
\nps -e -o pcpu,pid,user,tty,args | sort -n -k 1 -r | head
\nmpstat -P 0 2 20 (processor 0
\nmpstat -P ALL
\nsar -u -fDisk Storage<\/strong>
\n<\/strong>************************************<\/strong>
\niostat -d 3, iostat 2 15
\niostat -xd 10sorting files by size<\/strong>
\n<\/strong>***********************<\/strong>
\nls -alS | head -5
\nmpstat -P ALL
\nsar 4 5
\n****************************************************<\/strong>
\n<\/strong>Network<\/strong>
\n<\/strong>**************************************************<\/strong>
\nlsmod | grep -i bonding
\ncat \/etc\/sysconfig\/network-scripts\/ifcfg-eth0 (check bonding)..the difference NETWORK, IPADDRESS, NETMASK
\nnetstat -s | less
\nnetstat –interfaces eth0
\nnetstat -ptc
\nsar -n DEV
\nnetstat -nat | awk ‘{ print $5}’ | cut -d: -f1 | sed -e ‘\/^$\/d’ | uniq
\ntcpdump -n -i eth1 -s 0 -w output.txt src or dst port 80
\niptraf – Real-time Network Statistics
\nNetwork traffic<\/strong>
\nnetstat -ptc
\nsar -n DEV
\nsar – Collect and Report System Activity
\n*************************************************<\/strong>
\n<\/strong>Oracle<\/strong>
\n<\/strong>***************************************************<\/strong>
\ncpio -idmv < 10201_database_linux_x86_64.cpio
\nid oracle
\nid nobody
\npgrep sshd
\nenv | grep PATH<\/p>\n<\/div>\n
detected hardware\u00a0<\/strong>lshal:
\ninit process determines which runlevel it should be\u00a0<\/strong>\/etc\/inittab<\/div>\n
shutdown<\/strong>
\nshutdown -t3 -r now
\nmount \/dev\/hda4 \/data\/oracle\/bkup1:
\ngrep \u2018Ashley Nguyen\u2019 \/etc\/passwd
\nfind \/ -name install.log
\nsed \u2018s\/anguyen\/lvu\/\u2019 \/etc\/passwd > \/tmp\/test
\nps aux | grep nfs
\nfree:
\nIfconfig -a<\/div>\n
To determine the amount of shared memory available, enter the following command:automatic memory management
\n# df -k \/dev\/shm\/
\nTo determine the distribution and version of Linux installed, enter the following command:
\n# cat \/proc\/version
\nTo determine whether the required packages are installed, enter commands similar to the following:
\n# rpm -q package_name
\nAdd group<\/strong>
\n# \/usr\/sbin\/groupadd oper
\nModify user:\u00a0 <\/strong>usermod -g oinstall -G dba oracle
\nCreate disks:<\/strong>
\nfdisk -l<\/div>\n
give password to oracle user<\/strong>
\npasswd oracle<\/div>\n
change ownership in linux<\/strong>
\nchown<\/div>\n
clear screen <\/strong>
\nclear
\nTAR – backup \/ restore<\/strong>
\ntar -cf myfiles.tar *.trc (create)
\ntar xvf myfiles.tar (extract)<\/div>\n
<\/div>\n
<\/div>\n
\n

To create new directory<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
mkdir target_director<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To copy an entire folder (directory tree) in Linux<\/strong><\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n<\/td>\n
\n
\n
cp -ap \/var\/lib\/mysql \/mnt\/mysql -ap for same permission as source<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

For checking the size of current folder<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
du -ch | grep total<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To find the size of the hdd<\/strong><\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n<\/td>\n
\n
\n
just enter df<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To find out the size of the folder in the folder<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
du<\/code><\/div>\n
du -a to show all the file's size<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

See all files and their size<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
du -s * -h<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To output the number of files in the current directory<\/strong><\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n<\/td>\n
\n
\n
ls | wc -l<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

See all the jobs<\/strong><\/p>\n

\n
\n\n\n\n
\n
<\/div>\n<\/td>\n
\n
\n
ps -aux<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To find out RAM size on Linux machine<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
free<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Rename folder\/filename<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
mv test hope<\/code><\/div>\n
mv *.rtf *.txt<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To find which process is consuming how much RAM?<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
top<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To see the free ram memory<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
free -m<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To update yum using corn<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
\u00a021 *** usr\/bin\/yum -y update<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Create tar.gz file<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
tar czvf myfolder.tar.gz abcfolder\/<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Untar a tar file<\/strong>
\ntar czvf myfolder.tar.gz abcfolder\/
\n[\/sourcecode]<\/p>\n

Delete bash History<\/strong>
\nTry to delete the content of ~\/.bash_history<\/p>\n

To add new user<\/strong>
\n* Adding a new user (useradd)
\n* Modifying an existing user (usermod)<\/p>\n

Options:
\n* -d home directory
\n* -s starting program (shell)
\n* -p password
\n* -g (primary group assigned to the users)
\n* -G (Other groups the user belongs to)
\n* -m (Create the user\u2019s home directory<\/p>\n

\n
\n\n\n\n
\n
<\/div>\n<\/td>\n
\n
\n
useradd -gusers -Gmgmt -s\/bin\/shell -pass -d\/home\/jambura -m jambura<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

User\u2019s home directory should be 700. If you are operating a ~username type server, the public_html directory should be 777. You may also need to open up the home directory to 755.<\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
useradd -s\/bin\/bash -pass -d\/imp\/sysbsd -m sysbsd<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

For allowing sudo<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
sudo adduser jambura admin<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To delete user<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
userdel user<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

To display your crontab file<\/strong><\/p>\n

\n
\n\n\n\n
<\/td>\n\n
\n
crontab -l<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

root can view any users crontab file by adding \u201c-u username\u201d<\/strong><\/p>\n\n\n\n
<\/td>\n\n
\n
crontab -u bappy -l\u00a0 # List bappy's crontab file.<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

tar tvf myfiles.tar (show the details)<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

To view System Resource Information uname –help uname -r grep model \/proc\/cpuinfo grep MemFree \/proc\/meminfo sudo -u root lastcomm -f \/var\/account\/pacct cat \/proc\/version # cat \/proc\/cpuinfo # cat \/proc\/meminfo # cat \/proc\/zoneinfo # cat \/proc\/mounts cat \/etc\/redhat-release grep MemTotal \/proc\/meminfo grep SwapTotal \/proc\/meminfo df -k \/tmp grep “model name” \/proc\/cpuinfo ifconfig (\/sbin\/ifconfig) uaname -r lshal:detected […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/703"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=703"}],"version-history":[{"count":4,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/703\/revisions"}],"predecessor-version":[{"id":822,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/703\/revisions\/822"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=703"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=703"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=703"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}