UNIX 4 DBA (Part I)

Part 1 - Common UNIX Commands

These are the common UNIX commands Oracle DBAs would use. I have provided brief explanation of commands and examples. In UNIX, most commands have a lot of options available. For a complete list of options, see the UNIX online manual pages. All UNIX commands and file names are case sensitive. This page is to let you know the commands in UNIX, which might give you a start to learn more about the command using the manual pages or from UNIX books.

man man command Manual Pages - Help with any UNIX command
man ps Help on the UNIX ps command
clear clear To clear the screen
pwd pwd Present / Current Working Directory
cd cd [directoryname] Change directory, without argument will change your working directory to your home directory.
cd work Change working directory to "work"
cd .. Change working directory to parent directory (.. is parent and . is current directory)
ls ls [-options] [names] List files. [names] if omitted, will list all files and subdirectories in the directory. Wild cards can be specified.
ls -l List files with date and permissions
-rw-rw-r-- 1 oracle dba 706 Sep 23 17:26 storparms.sql

-rwxrwx--- 1 oracle dba 377 Aug 28 15:00 sysdelstat.sql

drwxrwxr-- 2 oracle dba 2048 Oct 22 16:12 work 
[column1]      [2]   [3] [4] [5]     [6]     [7] 

Column1 - Permissions of the file or directory; r-read, w-write, x-execute
Position 1 indicates if it is a directory
Positions 2-4 is the permission for owner
Positions 5-7 is the permission for group
Positions 8-10 is the permission for others
Column2 - Owner of the file/directory
Column3 - Group which the owner belogs to
Column4 - Size of the file in bytes
Column5 - Last Modified Date
Column6 - Last Modified Time
Column7 - Name of the file/directory

ls -al List files with date and permissions including hidden files
ls -lt List files with date, sorted in the date modified
ls -ltr bt* List files with date, sorted in the date modified, oldest first, with filenames starting with bt
Wildcards * Any character, any number of positions
? Any character, one position
[] A set of characters which match a single character position.
- To specify a range within []
ls *x* List all files which contains an x in any position of the name.
ls x* List all files which start with x
ls *T0[1-3]ZZ List all files which contain T0 followed by 1,2 or 3 followed by ZZ. The following files match this condition:
ls job?.sql List files which start with job followed by any single character followed by .sql

Example: jobd.sql jobr.sql

ls alert*.???[0-1,9]
touch - touch filename Create a 0 byte file or to change the timestamp of file to current time (wild cards as above can be used with the file names)
mkdir mkdir directoryname Create Directory
mkdir -p directorypath Create directory down many levels in single pass

mkdir -p /home/biju/work/yday/tday

rmdir rmdir directoryname Remove directory
rm rm filename Remove file
rm -rf directoryname Remove directory with files. Important - There is no way to undelete a file or directory in UNIX. So be careful in deleting files and directories. It is always good to have rm -i filename for deletes
cp cp filename newfilename Copy a file
cp -r * newloc To copy all files and subdirectories to a new location, use -r, the recursive flag.
mv mv filename newfilename Rename (Move) a file. Rename filename to newfilename.
mv filename directoryname Move filename under directoryname with the same file name.
mv filename directoryname/newfilename Move filename to directoryname as newfilename.
mv * destination If you use a wildcard in the filename, mv catenates all files to one sigle file, unless the destination is a directory.
cp -i file1 file2
mv -i file1 file2
rm -i file*
Use the -i flag with rm, mv and cp to confirm before destroying a file.
file file filename To see what kind of file, whether editable. Executable files are binary and you should not open them.
file d* dbshut: ascii text
dbsnmp: PA-RISC1.1 shared executable dynamically linked -not stripped
dbstart: ascii text
dbv: PA-RISC1.1 shared executable dynamically linked -not stripped
demobld: commands text
demodrop: commands text
vi vi filename Edit a text file. Vi is a very powerful and "difficult to understand" editor. But once you start using, you'll love it! All you want to know about vi are here. More vi tricks later!!
cat cat filename See contents of a text file. cat (catenate) will list the whole file contents. Cat is mostly used to catenate two or more files to one file using the redirection operator.
cat file1 file2 file3 > files Catenate the contents of file1, file2 and file3 to a single file called files. If you do not use the redirection, the result will be shown on the standard output, i.e., screen.
more filename
page filename
Show the contents of the file, one page at a time. In more/page, use space to see next page and ENTER to see next line. If you wish to edit the file (using vi), press v; to quit press q.
tail tail -n filename To see the specified number of lines from the end of the file.
head head -n filename To see the specified number of lines from the top of the file.
pg pg filename To show the contents of the file, page by page. In pg, you go up and down the pages with + and - and numbers.
1 First Page of the file
$ Last Page of the file
+5 Skip 5 pages
-6 Go back 6 pages
ENTER Next page
- Previous Page
q Quit
/string Search for string
env env To see value of all environment variables.
To set an environment variable: In ksh or sh "export VARIABLENAME=value", Note there is no space between =.
In csh "setenv VARIABLENAME value"
echo $VARIABLENAME See value of an environment variable
echo echo string To print the string to standard output
echo "Oracle SID is $ORACLE_SID" Will display "Oracle SID is ORCL" if the value of ORACLE_SID is ORCL.
lp lp filename To print a file to system default printer.
chmod chmod permission filename Change the permissions on a file - As explained under ls -l, the permissions are read, write, execute for owner, group and others.
You can change permissions by using numbers or the characters r,w,x. Basically, you arrive at numbers using the binary format.

rwx = 111 = 7
rw_ = 110 = 6
r__ = 100 = 4
r_x = 101 = 5

chmod +rwx filename

chmod 777 filename

Give all permissions to everyone on filename
chmod u+rwx,g+rx,o-rwx filename

chmod 750 filename

Read, write, execute for owner, read and execute for group and no permission for others
chown chown newuser filename Change owner of a file
chgrp chgrp newgroup filename Change group of a file
chown newuser:newgroup filename Change owner and group of file
compress compress filename Compress a file - compressed files have extention .Z. To compress file you need to have enough space to hold the temporary file.
uncompress uncompress filename Uncompress a file
df df [options] [moutpoint] Freespace available on the system (Disk Free); without arguments will list all the mount points.
df -k /ora0 Freespace available on /ora0 in Kilobytes. On HP-UX, you can use "bdf /ora0".
df -k . If you're not sure of the mount point name, go to the directory where you want to see the freespace and issue this command, where "." indicates current directory.
du du [-s] [directoryname] Disk used; gives operating system blocks used by each subdirectory. To convert to KB, for 512K OS blocks, divide the number by 2.
du -s gives the summary, no listing for subdirectories
find Find files. find is a very useful command, searches recursively through the directory tree looking for files that match a logical expression. It has may options and is very powerful.
find /ora0/admin -name "*log" -print Simple use of find - to list all files whose name end in log under /ora0/admin and its subdirectories
find . -name "*log" -print -exec rm {} \; to delete files whose name end in log. If you do not use the "-print" flag, the file names will not be listed on the screen.
grep Global regular expression print to search for an expression in a file or group of files. grep has two flavours egrep (extented - expands wild card characters in the expression) and frep (fixed-string - does not expand wild card characters). This is a very useful command, especially to use in scripts.
grep oracle /etc/passwd to display the lines containing "oracle" from /etc/passwd file.
grep -i -l EMP_TAB *.sql to display only the file names (-l option) which contains the string EMP_TAB, ignore case for the string (-i option), in all files with sql extention.
grep -v '^#' /etc/oratab display only the lines in /etc/oratab where the lines do not (-v option; negation) start with # character (^ is a special character indicating beginning of line, similarly $ is end of line).
ftp ftp [hostname] File Transfer Protocol - to copy file from one computer to another
ftp AAAd01hp invoke ftp, connect to server AAAd01hp.
Connected to AAAd01hp.com.
220 AAAd01hp.com FTP server (Version Mon May 11 12:21:14 GMT 1998) ready.
Name (AAAd01hp:oracle): BIJU
program prompts for user name, enter the login name to AAAd01hp.
331 Password required for BIJU.
enter password - will not be echoed.
230 User BIJU logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ascii
Specifying to use ASCII mode to transfer files. This is used to transfer text files.
200 Type set to A.
ftp> binary
Specifying to use binary mode to transfer files. This is used for program and your export dump files.
200 Type set to I.
ftp> ls
To see the files in the remote computer.
200 PORT command successful.
150 Opening ASCII mode data connection for /usr/bin/ls.
total 8
-rw-rw-rw- 1 b2t dba 43 Sep 22 16:01 afiedt.buf
drwxrwxrwx 2 b2t dba 96 Jul 9 08:47 app
drwxrwxrwx 2 b2t dba 96 Jul 9 08:49 bin
-rw-rw-rw- 1 b2t dba 187 Jul 30 14:44 check.sql
226 Transfer complete.
ftp> get check.sql
transfer the file check.sql from the remote computer to the local computer. The file will be copied to the present directory with the same name. You can optionally specify a new name and directory location.
200 PORT command successful.
150 Opening BINARY mode data connection for check.sql (187 bytes).
226 Transfer complete.
187 bytes received in 0.02 seconds (7.79 Kbytes/s)
ftp> !ls
! runs commands on the local machine.
AAAP02SN a4m08.txt tom3.txt
ftp> put a4m01.txt /tmp/test.txt
transfer file from local machine to remote machine, under /tmp directory with name test.txt.
mail mail "xyz@abc.com" < message.log Mail a file to internet/intranet address. mail the contents of message.log file to xyz@abc.com
mail -s "Messages from Me" "xyz@abc.com" "abc@xyz.com" < message.log mail the contents of message.log to xyz and abc with a subject.
who who [options] to see who is logged in to the computer.
who -T Shows the IP address of each connection
who -r Shows when the computer was last rebooted, run-level.
ps ps process status - to list the process id, parent process, status etc. ps without any arguments will list current sessions processes.
ps -f ull listing of my processes, with time, terminal id, parent id, etc.
ps -ef as above for all the processes on the server.
kill kill [-flag] processid to kill a process - process id is obtained from the ps command or using the v$process table in oracle.
kill 12345 Kill the process with id 12345
kill -9 12345 To force termination of process id 12345
script script logfilename to record all your commands and output to a file. Mostly useful if you want to log what you did, and sent to customer support for them to debug. start logging to the logfilename. The logging is stopped when you do "exit".
hostname hostname displays the name of the computer.
uname uname -a to see the name of the computer along with Operating system version and license info.
date date displays the current date and time.
date "+%m%d%Y" displays date in MM/DD/YYYY format
cal cal displays calender of current month
cal 01 1991 Displays January 1991 Calender
telnet telnet [hostname] to open a connection to another computer in the network. Provide the alias name or IP address of the computer.
& command & add & to the end of the command to run in background
nohup command & no hangup - do not terminate the background job even if the shell terminates.
fg fg to bring a background job to foreground
bg bg to take a job to the background. Before issuing this command, press ^Z, to suspend the process and then use bg, to put it in the background.
jobs jobs to list the current jobs in the shell.
rcp rcp [-r] sourcehost:filename destinationhost:filename Remote copy. Copy files from one coputer to another. To set up the computer for remote copy and remote login (rlogin) will be discussed later.
rcp host1:/ora0/file1.txt host2:/ora0/temp/file1.txt Copy file from host1 to host2. If the computer name is omitted, the hostname is assumed.


You can identify the semaphore id of an Oracle SGA (this gives semaphores, shared memory sizes also) from Server Manager using the command "oradebug ipc"

SVRMGRL> connect internal
SVRMGRL> oradebug ipc

Part 2 - Using UNIX Commands

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Biju Thomas is Oracle7.3 OCP, Oracle8 OCP, 
Oracle8i OCP and Oracle9i OCA/OCP Certified DBA

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