Basic Linux Commands
Name: uname -a
description: Displays operating system bit(32-bit or 64-bit)
output: Linux LAB-PERF-01 2.6.32-220.el6.x86_64 #1 SMP Wed Nov 9 08:03:13 EST 2011 x86_64 x86_64 x86_64 GNU/LinuxName: uname -m
description: Displays operating system bit(32-bit or 64-bit)
output: x86_64Name: ps
description: displays list of running processes
output:
PID TTY TIME CMD
5748 pts/3 00:00:00 bash
6090 pts/3 00:00:00 ps
Name: ps -eaf | grep Tcat
description: displays list of processes which has name 'Tcat'Name: top
description: 'top' also same as 'ps'
output:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
61026 contest 20 0 5117m 1.2g 17m S 0.3 3.8 13:20.77 /home/contest/prd/j
60932 contest 20 0 55180 2196 1592 S 0.0 0.0 0:00.01 /usr/libexec/openss
Shot cuts: q --> Quit
z -->change style
c-->Additional info
Shift+o -->sort
k--> kill process
Name: free -m
description: Displays free memory space(In MB)
output:
total used free shared buffers cached
Mem: 32072 22123 9949 0 302 13877
-/+ buffers/cache: 7943 24129
Swap: 49151 0 49151
Name: free -g
description:displays free memory in gigabites(GB)
output:
total used free shared buffers cached
Mem: 31 21 9 0 0 13
-/+ buffers/cache: 7 23
Swap: 47 0 47
Name: ls
description:list the file and directories
output:
ant jacoco prd test
a.txt jacoco_contest rollbackPatch.retry testjava
bkp jacoco.tar settlement tiles.xml
installPatch.retry keystore sftp uninstall.retry
install.retry logs TcatConnect
Name: ls -l
description: displays links(with file and folder permissions)
output:
total 13968
drwxrwxr-x 3 contest contest 63 Sep 1 2014 ant
-rw-r--r-- 1 contest contest 1430 Nov 6 2015 a.txt
drwxrwxr-x 3 contest contest 44 Apr 15 13:15 bkp
-rw-rw-r-- 1 contest contest 14 Apr 22 20:08 installPatch.retry
-rw-rw-r-- 1 contest contest 13 May 10 14:57 install.retry
drwxrwxr-x 6 contest contest 112 May 23 15:59 jacoco
drwxrwxr-x 3 contest contest 16 Sep 22 2014 jacoco_contest
-rw-rw-r-- 1 contest contest 14254080 Jun 23 12:39 jacoco.tar
-rw-rw-r-- 1 contest contest 1371 Dec 3 2015 keystore
drwxrwxr-x 2 contest contest 6 Aug 19 2015 logs
drwxrwxr-x 8 contest contest 4096 Mar 10 14:29 prd
-rw-rw-r-- 1 contest contest 14 Apr 22 19:35 rollbackPatch.retry
drwxrwxr-x 4 contest contest 4096 Apr 13 2015 settlement
drwxrwxrwx 4 contest contest 44 Aug 7 2014 sftp
drwxrwxr-x 2 contest contest 22 Nov 23 2015 TcatConnect
drwxrwxr-x 3 contest contest 43 Nov 18 2015 test
drwxrwxr-x 4 contest contest 34 Jun 26 2015 testjava
-rw-rw-r-- 1 contest contest 15726 Dec 11 2014 tiles.xml
-rw-rw-r-- 1 contest contest 14 Apr 6 17:42 uninstall.retry
Name: uptime
description:displays server up time
output:
17:00:18 up 68 days, 2:43, 6 users, load average: 0.06, 0.07, 0.06
Name: w
description: displays number of users logged in and from where they logged in.
output:
17:00:40 up 68 days, 2:44, 6 users, load average: 0.05, 0.06, 0.05
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
root tty3 - 11May16 50days 0.03s 0.03s -bash
contest pts/0 mckd-5382.comviv Wed18 22:43m 3.29s 3.28s tailf catalina.
contest pts/1 :1.0 20May16 41days 0.01s 0.01s -bash
contest pts/2 mckd-5382.comviv Wed18 22:35m 13:24 0.01s -bash
contest pts/3 mckd-5377.comviv 16:45 0.00s 0.03s 0.01s w
root tty1 :0 11May16 68days 12:22 12:22 /usr/bin/Xorg :
Name: w -u root
description: displays how many users logged in as root
output:
17:02:49 up 68 days, 2:46, 6 users, load average: 0.00, 0.04, 0.04
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
root tty3 - 11May16 50days 0.03s 0.03s -bash
root tty1 :0 11May16 68days 12:22 12:22 /usr/bin/Xorg :
Name: sar
description: displays core of CPU
output:
Linux 2.6.32-220.el6.x86_64 (LAB-PERF-01) 06/30/2016 _x86_64_ ( 4 CPU)
Name: iostat
description: displays statistics of cpu and disk (-c will give only cpu stats and -d will give only disk stats)
output:
Linux 2.6.32-220.el6.x86_64 (LAB-PERF-01) 06/30/2016 _x86_64_ (4 CPU)
avg-cpu: %user %nice %system %iowait %steal %idle
1.87 0.00 1.10 0.01 0.00 97.02
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 8.05 1.92 1404.75 11303270 8267325638
dm-0 0.00 0.00 0.00 5240 0
dm-1 3.08 0.42 663.48 2457985 3904786737
dm-2 1.15 0.07 176.36 429989 1037912909
dm-3 0.49 0.00 9.60 8465 56508262
dm-4 2.29 0.36 530.17 2095847 3120198667
dm-5 0.11 0.26 4.78 1549926 28133787
Name: lsof
description:displays list of open file
output:
java 61026 contest 272r REG 253,5 189401 42138737 /home/contest/prd/TcatConnect/mule-libs/opt/jgrapht-jdk1.5-0.7.3.jar
java 61026 contest 273r REG 253,5 152797 42138741 /home/contest/prd/TcatConnect/mule-libs/opt/jdom-1.1.1.jar
java 61026 contest 274r REG 253,5 391588 42138747 /home/contest/prd/TcatConnect/mule-libs/opt/wss4j-1.6.3.
Name: lsof -u root
description:displays list of files opened by user root
Name: lsof -i
description: list the internet connection.
Name: lsof -i:9888
description:display which process is using port 9888
Name: lsof -i tcp:9888
description:display which process is using tcp port 9888
Name: lsof -i tcp:1-1000
description:display which process is using tcp port from 1 to 1000(range)
Name:less
description:'less' is using to display file content(shift+g will show bottom of file)
Name:tailf
description:displays live content of file(ex: end of log file)
How to view cron jobs?
crontab -e
How to switch user ?
su - <user-name> then it may ask for user password
How to view cron jobs?
crontab -e
How to switch user ?
su - <user-name> then it may ask for user password
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