[Linux] - Unix/Linix Commands 1. $ ssh username@servername command used to login to server 2$ pwd it prints present working directory 3$ ls -l listing the files in present directory 4$ cd..takes you to previous Dir 5$ mkdir <directory>will create directory 6$ mkdir -p /home/user1/d1/d2/d3will create all the non-existing Dir’s 7$ vi <file_name>opens file for reading/editing 8$ cat <file_name>display contents of file 9$ more <file_name>displays page by page contents of file 10$ grep <pattern> file_namechecks pattern/word in file name specified 11$ head <file_name>shows first 10 lines of file_name 12$ touch <file_name>creates a zero/dummy file 13$ ln file1 file2 creates link of file1 to file2 14$ cp <file1> <file2>Copy a file 15$ mv <file1> <file2>Move/rename a file or folder 16$ clearclears the scree 17$ whoDisplays logged in user to the system. 18$ file <file_name>shows what type of file it is like 19$wwill display more info abt the users logged in 20$ ps -efshows process 21$ which <file_name>shows if the file_name/command exists and if exists display the path 22$ rm <file_name>will delete file specified$ rm * Delete all the files in the present directory (BE CAREFUL WHILE GIVING THIS COMMAND) 23$ find . -type f -print -exec grep -i <type_ur_text_here> {} \;this is recursive grep$ find / - name <file_name> -print 24$ tail <file_name>shows last 10 lines of fileuse tail -f for continous update of file_name 25$ chmod 777 <file_name>changes file_name/directory permissions use –R switch for recursive 26$ chown owner:group <file_name>changes owner & group for the file_name 27$ chgrp <groupname> <filename>use –R for recursive 28$ rsh -l <login_name> <server_name> 29$ rcp file1 file2Copying file to remoter servers (This requires pre-configuration on remote servers like .rhosts & hosts.equiv) 30$ gunzip <file_name>unzips file name$ gzip <file_name>zips file_name 31$uncompress <filename>uncompresses filename 32$ compress <file_name>compresses file_name 33$ bc -lbench calculator 40$ crontab -lShows the cron jobs running/scheduled for the current user.-->$crontab -l > present_cronjobs-->edit/add entries to present_cronjobs-->$crontab present_cronjobs (This will submit/resubmit the jobs in file presnt_cronjobs to CRON) 41$ at$ at -l will show the at jobs scheduledat – schedule a job to run later timeat <time> command/script (will run the script at specified time) 42killing an unwanted process$ps –ef | grep <process_name> (will show the PID of the process in the 2nd field)$kill -9 <PID>$ kill -3 <PID>Used to take threaddump of java process 43$ nohup <cmd_name> &nohup is very useful command. it runs the command even the telnet connection is closed/broken.& is used for running command in background. 44$ uptimewill show how long the system has been up and also shows cpu load, number of users logged in etc. 45$ lastWill show the users logged in/out informationlast <user_name> shows particular user logins/logoutslast reboot shows all the system boots 46$ idshows current user's UID, username and GID and group name 47$ hostidshows unique identifier of host 48$ uname -awill show system name, solaris version, platform and some more information 49$ isainfo -vshows supported platforms (32-bit, 64-bit) 50$ hostnamewill give your system name. 51$ envList the environmental variables set to your current session 52$ rm - <-filename>for deleting special files$ rm "<file name>"delete file names with spaces in between 53$ useradd <username>Adding a user to the system$ userdel <username>Deleting a user from the system 54$ echo $TERMShows terminal type like vt100, vt220 etc.($PATH, $ORACLE_HOME etc can be used with echo) 55$ du –sk <dir/file name>Display the size of the files/folder 56$ df -kwill show all the mounted filesystems. 57$ mountwill show all mounted file systems with additional info like large filesystem support etc 58$ pkginfo Gives/shows info about installed packages/software on system 59$ showrev –pshows all patches installed on system 60$ init 0will shutdown the system 61$ init 6will reboot the system (other init options are 1, 2, 3, 5 and S) 62$ alias l='ls -l'alias dir='ls -l|grep "^d"'alias p='pwd'alias c='clear'Short cuts for commonly used commands 63tar -cvf allfile.tar /<directory_name> copies all files under directory to allfile.tar$ tar -xvf allfile.tar /homeretrieves tar files to /home directory$ tar -tvf allfile.tar reads contents of allfile.tar 64$ /usr/sbin/ifconfig -aWill show the ip-address of the system.lo0 : loopback interfacehme0 : hundred MBPS n/w interfaceqfe0 : quad ehternet interface 65$ ping <hostname>will ping and test connectivity between your system and the hostname you give in the ping.you can also give ping <ip-address> 66$ set -o viWhile your shell is set to KSH use this command to display history of commands you are typingPress ESCAPE and k for showing previous commands 67$ ifconfig unplumb hme0 will disable ehternet interface hme0 68$ ifconfig plumb hme0 will enable hme 069$ mount will show the disks mounted and all partitions 70$ top shows all process and memory, cpu etc utilisation 71$ prtconf shows h/w, cpu, memory conf 72$ cd /usr/platform/sun4u/sbin/prtdiag -v shows additional configuration of memory, cpu speed etc.. 73$ sysdef shows system h/w, memory, and other internal configurable/tunable paramters 74$ sar –A system archive report, gives total system report for cpu, memory, disk, etcc 75$ mpstat shows multi cpu statistics like load on each cpu. 76$ iostat disk utilisation, cpu, io wait etc (iostat -xcM gives extented statistics of disk activity, cpu etc) 77$ vmstat memory and virtual memory utilization 78$ prstat shows process related statistics (present from solaris 2.7 and above) 79$ netstat shows network statistics 80$ lsof -p <pid>List the opened files for the process 81$ psrinfo gives processor/s information (online/offline) 82$ truss -p <PID>shows system calls and signals (useful when debugging process) 83$ stty erase ^Hsets backspace for deleting typed character 84$ strings <file_name>shows printable strings in any type of file (binary, object, text etc) 85$ formatwill show all the disks configuration and partitions 86$ prtvtoc shows disk partition/geometry info 87$ uadmin 2 0 stops system immediately within 5 seconds(BE CAREFUL-- has to be to root) 88$ halthalts processor and reboots machine (BECAREFUL -- has to be root) 89$ adb debugging tool (for reading/debugging corefiles) 90$ dos2unix <filename>Convert dos formatted file to unix format 91$ mkfile 60m <swap file name>creates a filename of size 60mb which can be used for adding to swap space 92$ swap -a <swap file name>attaches the 60mb file to swap space (Very useful when swap space is running out) 93$ swap -l lists the swap contents 94$ sleep 5waits for 5 seconds (useful in shell scripts) 95$ cat <file_name> |awk '{print $1}'Prints the first field of the filed ($1, $2... can be used to display more fields) 96:1,$s/<old>/<new>/guse the above for global replacement of text in ascii files using vi editor 97:1,$s/^M//gremove Ctrl M character in text files using vi editor 98$ ksh –x <file name.sh>Will compile the shell file line by line 99PS1=[$(hostname)]'$ORACLE_SID@$PWD>'Add this entry on .profile , you can view the hostname , $VARIABLE,current directort path 100$ipcs –mbWill provide the shared memory information 101$ mailx -s"<Subject Name>" [email protected] < file.txtWill send this file.txt to a mail$ uuencode $file $file| mail -s "<Subject Name>" [email protected] send the files as an attachment. Important Directories to Remeber / Root Directiry of unix system /usr/bin This directory cotains all user level unix commands /usr/sbin This directory Contains administrative related commands /usr/lib This directory contains libraries /etc This directory contains system configuration files /var/adm This directory contains system/application logs. /etc/rc.d This directory Contains all startup scripts.There will be more of this kind rc2.d, rc3.d, rc0.d, rc5.d, rc6.d each directory has scripts which will run in its own run level. /opt In general, this directory used to install the 3rd party optional packages. /proc This contains the snapshot of the system process and memory status. Important files to remember /etc/passwd it will show all the logins, home directories of the users. /etc/shadow shows password encryption info and other user related info (only root has access to this file) /etc/system This file has all n/w, h/w, memory etc tunable parameters /values/etc/inittab This file defines the default run level of the system. /etc/hosts This file contains the list of hosts/IP address /etc/services This file contains the port/service Name /etc/nsswitch.conf This file is used to configure which services are to be used to determine information such as hostnames, password files, and group /etc/ntpd.conf This file is used to configure Network Time Deamon /etc/inetd.conf This file tells which ports to listen to and what server to start for each port /etc/syslog.conf This file have the configuration log file location and rotation sequence /etc/sudoers contains the list of user names with the command allowed to execute by the user with additional privileges /etc/fstab This file contains the list of file system and it mount points /etc/resolv.conf contains the DNS server names for the name resolution 1) Editing the FILE:- -------------------------- *) To come to end of file:- G *) To delete the single word(can be free space):- dw *) to delete the current single char:- (Esc and x) *) To delete the complete line:- dd *) To right over in the file:- cw *) To remove the case sensitive:- :set ic *) To Enable the case sensitive:- :set noic *) Copy the complete line:- yy *) Paste what ever copied:- p 2) GUN ZIP the file:- ----------------------------- gzip file_name Note:- While trying to download gunzip file from server to local machine it should be done in binary mode.