UNIX Basics for the DBA

Basic UNIX Command
The following is a list of commonly used Unix command:

ps - Show process
grep - Search files for text patterns
mailx - Read or send mail
cat - Join files or display them
cut - Select columns for display
awk - Pattern-matching language
df - Show free disk space

Here are some examples of how the DBA uses these commands:

List available instances on a server:

$ ps -ef | grep smon
oracle 21832     1 0   Feb 24 ?       19:05 ora_smon_oradb1
oracle   898     1 0   Feb 15 ?        0:00 ora_smon_oradb2
    dliu 25199 19038 0 10:48:57 pts/6    0:00 grep smon
oracle 27798     1 0 05:43:54 ?        0:00 ora_smon_oradb3
oracle 28781     1 0   Mar 03 ?        0:01 ora_smon_oradb4

List available listeners on a server:

$ ps -ef | grep listener | grep -v grep
oracle 23879    1 0   Feb 24 ? 33:36 /8.1.7/bin/tnslsnr listener_db1 -inherit
oracle 27939    1 0 05:44:02 ? 0:00 /8.1.7/bin/tnslsnr listener_db2 -inherit
oracle 23536    1 0   Feb 12 ? 4:19 /8.1.7/bin/tnslsnr listener_db3 -inherit
oracle 28891    1 0   Mar 03 ? 0:01 /8.1.7/bin/tnslsnr listener_db4 -inherit

Find out file system usage for Oracle archive destination:

$ df -k | grep oraarch
/dev/vx/dsk/proddg/oraarch 71123968 4754872 65850768 7% /u09/oraarch

List number of lines in the alert.log file:

$ cat alert.log | wc -l
2984

List all Oracle error messages from the alert.log file:

$ grep ORA- alert.log
ORA-00600: internal error code, arguments: [kcrrrfswda.1], [], [], [], [], []
ORA-00600: internal error code, arguments: [1881], [25860496], [25857716], []

CRONTAB Basics

A crontab file is comprised of six fields:

Minute	0-59
Hour	0-23
Day of month	1-31
Month	1 - 12
Day of Week	0 - 6, with 0 = Sunday
Unix Command or Shell Scripts

To edit a crontab file, type:

Crontab -e

To view a crontab file, type:

Crontab -l

0 4 * * 5 /dba/admin/analyze_table.ksh
30 3 * * 3,6 /dba/admin/hotbackup.ksh /dev/null 2>&1

In the example above, the first entry shows that a script to analyze a table runs every Friday at 4:00 a.m. The second entry shows that a script to perform a hot backup runs every Wednesday and Saturday at 3:00 a.m.

Top DBA Shell Scripts for Monitoring the Database

The eight shell scripts provided below cover 90 percent of a DBA's daily monitoring activities. You will need to modify the UNIX environment variables as appropriate.

Unix and Oracle

UNIX Basics for the DBA