Quick UNIX and LINUX notes for Oracle DBAs

The following are the commands that you, as a DBA,

 do not need to know but it is good to know.

INDEX

cpio

Copy file archives in and out.

Example:

$cd /etc                                                  #Go to directory that you want to have a backup.

$ls | cpio –oc > /u01/cpio_bkup                #Copy all files in /etc to the /u01/cpio_bkup file.

$mkdir /u01/copyhere                      #Make a directory.

$cd /u01/copyhere                      #Change directory to the created directory.

$cat /u01/cpio_bkup | cpio –ic  #Read cpio_bkup file and copy all data into the current directory.

$ls | cpio –oc > /dev/rmt/0                              #Copy all ls output files into tape device.

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devfsadm

Administration command  for  /dev  and    /devices.

Example;

$cd /dev/rmt                                          #Check the content of the /dev/rmt directory.

$devfsadm –c tape                        #A new tape device was added to the system.

$cd /dev/rmt                                          #Check the differences.

$mt status                                              #Check your magnetic tape status.

$dttape init /dev/rmt/0 –volume X                #Initialize the tape using datatools.

$obacktrack                                           #Use obacktrack if you have sqlback track.

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format

Disk partitioning and maintenance utility (Unix/Solaris only).

Example;

$format                                                   #Disk partitioning and maintenance utility.

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init

Initialize your server.

Example:

$su root

$init 0                                                     #Shutdown the server and have OK prompt.

$init 6                                                     #Reboot the server.

$reboot                                                  #Reboot the server.

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boot

On the OK prompt, you can boot.

Example:

$ok boot                                                #Boot from default disk.

$ok boot cdrom                                    #Boot from cdrom

$ok boot 2th_boot_disk                      #Boot from a different boot disk.

$ok nvalue /2th_boot_disk /…/….    #Define an alias for the second boot disk.

$ok nvstore                                           #Save the alias.

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groupadd

Add a Unix/Linux group account.

Example:

$more /etc/group|grep dba                         #Check to see if the group exists.

$groupadd –g dba                         #If not add a group.

$more /etc/group|grep dba                         #Check to see that the group was added.

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groupdel

Delete a Unix/Linux group account.

Example:

$more /etc/group|grep dba                         #Check to see if the group exists.

$groupdel dba                                      #Delete a group.

$more /etc/group|grep dba                         #Check to see that the group was deleted.

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isainfo

Describe instruction set architectures.

Example:

$isainfo –v                                            #Describe instruction set architectures (64bits or 32bits).

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java

Display java version or other information.

Example:

$java –version                                      #Display java full version.  

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ln

Assign a symbolic link.

Example:

$cd /u01                                                 #Change your directory.

$df –k > myfile                                      #Create a file that contains disk space allocation.

$more myfile                                          #Display the file content.

$mkdir mylinkdir                                   #Create a directory for all your links.

$ln –s /u01/myfile /u01/mylinkdir/mylink

                                                                #Create a link.

$more /u01/mylinkdir/mylink          #Display the link file content.

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mount

Mount a device.

Example:

$mount /dev/rmt/1 /mnt                     #Mount a second external tape device.

$mount /dev/dsk/c3t1d0s0 /mnt     #Mount a disk device.

$mount 127.0.0.1:/cdrom/cdrom0 /mnt

                                                                #Mount your disktop cdrom or if a server does not have cdrom.

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mt

A device status.

Example:

$mt -f /dev/rmt/0 status

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patchadd

Apply single patch to your O/S.

Example:

$patchadd patch_number                      #Add a single patch to your O/S.

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patchadd

Add multiple patches to your O/S.

Example:

$cd /../patches                                      #Change directory to downloaded patches.

$for i in ‘ls –l 1*’;do                    #For all patches that their numbers start from 9.

$patchadd $i                                         #Read each patch number.

$done                                                     #Apply patches.

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patchrm

Remove a single patch from your O/S.

Example:

$patchrm patch_number                      #Remove a single patch from your O/S.

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prtconf

Print system configuration.

Example:

$prtconf                                         #Print all system configuration.

$prtconf | grep Mem                       #Print the size of system memory.

$prtstat   #For memory usage

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psrinfo

Print process system configuration.

Example:

$psrconf -v                                                 #Print all process system configuration.

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showrev

Display the latest release of your applied patches.

Example:

$showrev –p |grep patch_number                #Display the latest information about your patches.

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symsm  

Symplicity Storage Manager Tool

Example:

$/usr/lib/symsm/bin/symsm &     #Execute the Symplicity Storage Manager Tool.

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sync

Synchronize your system. Do this before your shutdown.

Example:

$sync;sync;sync;halt                         #Before halting your system, synchronize the system.

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tar

Tar to a tape.

Example:

$cd /u01/app/oracle                    #Change to a directory that you want to tar all information to a tape.

$tar –cvf  /dev/rmt/0 .                            #Copy all the current information to a tape.

$tar –tvf /dev/rmt/0                              #Display the tape table of contents.

$tar –xvf /dev/rmt/0                              #Extract files from tape.

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umount

Un-mount the file system device.

Example:

$cd /                                                       #Go to route sub-directory.

$mkdir u01                                             #Make a directory.

$mount /dev/dsk/c3t1d0s5 /u01     #Mount it.

$cd /u01                                                 #Change your current directory to /u01. Add files to it.

$cd /                                                       #Go back to route directory (make sure you are not using /u01 device).

$umount                                                                #umount it.

$cd /u01                                                 #Change your current directory to /u01 (what do you see?).

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uname

Print name of current system.

Example:

$uname –a                                             #Print name of current system with all information (-a).

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ufsdump

Dump a system file incrementally.

Example:

$umount                  /u01                                        #Un-mount the device that you want to do a dump.

$ufsdump 0uf /dev/rmt/0 /dev/rdsk/c3t1d0s0

                                                                #Dump un-mounted device into a tape.

$ufsdump 0uf /u01dump /dev/rdsk/c3t1d0s0

                                                                #Dump un-mounted device into a disk.

                                                                # 0 – all files, u – update the dump record, f – file system device.

$mount /dev/rdsk/c3t1d0s0 /u01     #Mount the device that you have dumped.

#Don’t forget when you un-mount and mount a file system, change the vfstab file also if needed.

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ufsrestore

Restore a system file.

Example:

$mount /dev/rdsk/c3t1d0s0 /u01     #Mount the device that you want to restore a file system.

$cd /u01                                                 #Change the directory to the mounted device.

$ufsrestore tvf /dev/rmt/0                              #Show the table of contents from tape.

$ufsrestore rvf /dev/rmt/0                              #Restore recursively from tape to /u01.

                                                                # r – restore recursively, v – verbose, and f - file system device.

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useradd

Add a Unix/Linux user account.

Example:

$more /etc/shadow|grep oracle     #Check to see the Oracle user exists.

$userdel –r oracle                                 #Delete it and also its default directory.

$mkdir /home/app                                #Make the Oracle default directory.

$chown oracle /home/app                             #Change its owner to the ‘oracle’ user.

$useradd –u 1001 –d /home/app –s /bin/ksh oracle

                                                                #Create oracle user with default directory /home/app and

                                                                #user id 1001, password ‘pass’ and default shell (korn shell).

$more /etc/shadow|grep oracle     #Check to see the user was added.

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userdel

Delete a Unix/Linux user account.

Example:

$more /etc/shadow|grep oracle     #Check to see the Oracle user exists.

$userdel –r oracle                                 #Delete it and also its default directory (-r remove the default directory).

$mkdir /home/app                                #Make the Oracle default directory.

$chown oracle /home/app                             #Change its owner to the ‘oracle’ user.

$useradd –u 1001 –d /home/app –s /bin/ksh –p pass oracle

                                                                #Create oracle user with default directory /home/app and

                                                                #user id 1001, password ‘pass’ and default shell (korn shell).

$more /etc/shadow|grep oracle     #Check to see the user was added.

$userdel –r oracle                                 #Delete it and also its default directory (-r remove the default directory).

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SQL Backtrack

To backup your Oracle data, you may have sql-backtrack. Remember the following function.

Example:

$obacktrack                                           #Run SQL backtrack interactively.

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Networker

Quick and simple commands.

Example:

$/usr/bin/nsr/networker start                #Start networker.

$/usr/bin/nsr/networker stop                #Stop networker.

$/usr/sbin/nsr/nsrjb –Hev                 #Diagnose networker.

$tail /usr/logs/messages                            #Check error messages.

$tail -100 /usr/logs/daemon.log         #Check logs.

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Managing your disk (Unix/Solaris only):

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Important Network UNIX files:

/etc/hosts

                127.0.0.1                localhost                 localhost.domain.name

/etc/nsswitch.dns

                hosts:                     dns, files

/etc/resolv.conf

                domain                   domain_name

                nameserver                155.33.222.140

                search                    domain_name

/etc/defaultrouter

                127.0.0.1                #Router IP address.

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Important Network LINUX files:

Basic linux network configuration files:

Making the following gross assumptions:

Your IP is:           192.168.0.1

Your Gateway is:      192.168.0.254

Your netmask is:      255.255.255.0

Your nameservers are: 192.168.0.2, 192.168.0.3, and 192.168.0.4

/etc/sysconfig/network

======================

NETWORKING=yes

HOSTNAME=your_machine_name.saa.senate.gov

GATEWAY=192.168.0.254

/etc/hosts

==========

127.0.0.1     localhost.localdomain             localhost

192.168.0.1   your_machine_name.company.com  your_machine_name

192.168.0.254 your_gateway.company.com       your_gateway

(You don't absolutely *need* your gateway in the hosts file, 

but I feel it does sometimes speed up some operations)

/etc/sysconfig/network-scripts/ifcfg-eth0

=========================================

DEVICE=eth0

BOOTPROTO=none

ONBOOT=yes

IPADDR=192.168.0.1

NETMASK=255.255.255.0

/etc/resolv.conf

================

search gateway compay_gateway

nameserver 192.168.0.2

nameserver 192.168.0.3

nameserver 192.168.0.4

(The 'search' line is optional. You can have 

up to 3 'nameserver' lines,and they don't need to be inside your network)

Generic Linux documentation can always be found at: http://www.tldp.org

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Important Network Information:

IP address:

Netmask:

Network:

Broadcast:

Hostname:

Gateway:

Primary DNS:

Secondary DNS:

Ternary DNS:

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Important Notes to disable or enable Linux components:

How to disable or enable Software component in LINUX for example telnet.

First list or check to see if your software is on or off.

$chkconfig –list (you must be as root)

Open the "/etc/xinetd.d/telnet" file.

 You get something like this:

[oracle@linux xinetd.d]$ more telnet

# default: on

# description: The telnet server serves telnet sessions; it uses \

# unencrypted username/password pairs for authentication.

service telnet

{

        flags           = REUSE

        socket_type     = stream       

        wait            = no

        user            = root

        server          = /usr/sbin/in.telnetd

        log_on_failure  += USERID

        disable         = no

}

Change the disable parameter to "no" or "yes" in order to disable or enable the telnet session.

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Apache Web Server:
What is Apache? 
Apache was originally based on code and ideas found in the most popular HTTP server of the time.. NCSA httpd 1.3 (early 1995). It has since evolved into a far superior system which can rival (and probably surpass) almost any other UNIX based HTTP server in terms of functionality, efficiency and speed. Since it began, it has been completely rewritten, and includes many new features. Apache is, as of January 1997, the most popular WWW server on the Internet.

Why the name "Apache"? 
A cute name which stuck. Apache is "A PAtCHy server". It was based on some existing code and 
a series of "patch files".


find / -name httpd.conf       #find the httpd.conf file.
cp /etc/apache/httpd.conf-sample /etc/apache/httpd.conf    #copy sample and change the httpd.conf file.
edit /etc/apache/httpd.conf if the port 80 is in used.
edit /etc/apache/jserv.properties to point to correct java version. Ex: wrapper.bin=/usr/java/bin/java

check /var/apache/logs/errors.log if you cannot start the web server.

ps -ef|grep apache  #check the web server was started.

Start and stop web server:
/usr/apache/bin/apachectl start
/usr/apache/bin/apachectl stop
/usr/apache/bin/apachectl restart

Web server version:
/usr/apache/bin/httpd -v

netstat -an | grep 80   #check the port 80 is in used.

How to reset your log files
Sooner or later, you'll want to reset your log files (access.log and error.log) because they are too big, or full of old information you don't need. access.log typically grows by 1Mb for each 10,000 requests. Most people's first attempt at replacing the logfile is to just move the logfile or remove the logfile. This doesn't work. Apache will continue writing to the logfile at the same offset as before the logfile moved. This results in