Here is a simple way to output SQL query output into a file, via command line based SQLPlus.

Step 1: Nominate the output file location. In this case this is a Unix location.

SQL> spool /tmp/output.txt

Step 2: Perform your SQL query.

SQL> select * from tab;

Step 3: Close the file.

SQL> spool off

Tip: Use set lines statement to adjust output display

The other method is doing this outside of SQLPlus in a single command.  Within the Unix shell, you can write your SQL query statements within an input sql file; eg input.sql, and redirect the output to output.txt.

# sqlplus USER/PASS@DBSID < /tmp/input.sql > /tmp/output.txt

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This simple guide to shows how to start /stop your Oracle database from Unix.  You must have logon access to do this.

Step 1

Unix login as oracle (usually the user that installed the database)

Step 2

Make sure your environment variables are set, eg:

ORACLE_SID=MYDBSID
ORACLE_BASE=/opt/oracle
ORACLE_HOME=/opt/oracle/product/11.2.0/dbhome_1
LD_LIBRARY_PATH=/opt/oracle/product/11.2.0/dbhome_1/lib
PATH=/usr/bin:/usr/sbin:/usr/ucb:/usr/local:/usr/local/bin:/usr/local/sbin:/opt/oracle/product/11.2.0/dbhome_1/bin

Step 3 – Start DB Instance

On the Unix command line, run sqlplus with sysdba, and simply type startup in the prompt to start it up.

oracle@db-srv-01 % sqlplus '/ as sysdba'

SQL*Plus: Release 11.2.0.1.0 Production on Tue Nov 30 12:06:47 2010

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 3207790592 bytes
Fixed Size                  2152368 bytes
Variable Size            2449475664 bytes
Database Buffers          738197504 bytes
Redo Buffers               17965056 bytes
Database mounted.
Database opened.

Step 4 – Start Listener

To start the oracle listener (assuming listener.ora is setup), run lsnrctl start

oracle@db-srv-01 % lsnrctl start

LSNRCTL for Solaris: Version 11.2.0.1.0 - Production on 30-NOV-2010 12:00:34

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Starting /opt/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Solaris: Version 11.2.0.1.0 - Production
System parameter file is /opt/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Log messages written to /opt/oracle/diag/tnslsnr/db-srv-01/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=db-srv-01)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=db-srv-01)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Solaris: Version 11.2.0.1.0 - Production
Start Date                30-NOV-2010 12:00:35
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /opt/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Listener Log File         /opt/oracle/diag/tnslsnr/db-srv-01/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=db-srv-01)(PORT=1521)))
The listener supports no services
The command completed successfully

Step 4 – Shutdown

Similarly, to shutdown the instance, type shudown normal within sqlplus.

Stop the listener, by running lsnrctl stop

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Here is a simple unix shell command to check if a directory, $dir, is empty.

export $dir=/tmp/myfiles/
if [ "$(ls -A $dir)" ];
then
    echo "$dir NOT Empty";
else
    echo "$dir IS Empty";
fi

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Having command line text in colors makes things easier to read.  For example the ls command for listing directories and files.  In some Unix environments, the ls command may not support the –color option to let us do that (as it  requires GNU ls).  So how can we workaround this to add color to ls?

Here are my steps to make it happen. Note i’m no Unix guru, and I didn’t have time to perfect it.. but it gets the job done!

1) Basic test. Echo some random color text.  I had to specify the full path of echo to make it work. The value 01;34 is the color code for light blue.

/bin/echo "\033[0m\033[01;34mthis is blue text\033[0m"

2) Here are some other color codes.

Black       0;30     Dark Gray     1;30
Blue        0;34     Light Blue    1;34
Green       0;32     Light Green   1;32
Cyan        0;36     Light Cyan    1;36
Red         0;31     Light Red     1;31
Purple      0;35     Light Purple  1;35
Brown       0;33     Yellow        1;33
Light Gray  0;37     White         1;37

3) Here are the ls commands I would like to color… with a bit of help from Google somewhere.

ls -ld .*/             # List hidden directories
ls -ld */              # List visible directories
ls -lAd .* |grep '^-'  # List hidden files
ls -l |grep '^-'       # List visible files

4) Combining 1 and 3, gives me the following commands:

/bin/echo "\033[0m\033[01;34m`ls -ld .*/`\033[0m"
/bin/echo "\033[0m\033[01;32m`ls -ld */`\033[0m"
/bin/echo "\033[0m\033[00;31m`ls -lAd .* |grep '^-'`\033[0m"
/bin/echo "\033[0m\033[01;33m`ls -l |grep '^-'`\033[0m"

5) Mash it together, assign it to an alias, and thats it! One single action does the job!

alias ll='/bin/echo "\033[0m\033[01;34m`ls -ld .*/`\033[0m" ; /bin/echo "\033[0m\033[01;32m`ls -ld */`\033[0m" ; /bin/echo "\033[0m\033[00;31m`ls -lAd .* |grep '^-'`\033[0m" ; /bin/echo "\033[0m\033[01;33m`ls -l |grep '^-'`\033[0m"'

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Via Unix/Linux:

cat /dev/zero > /dev/null

or

cp /dev/zero  /dev/null

Explaination:

/dev/null is basically a black hole (a special null file), anything written to it goes down the drain.  Anything read from it will result in nothing returned.  /dev/zero is basically the same as /dev/null when writing to it, however reading it will result in a continuous stream of zeros without EOF.

I have a large file.

How can i split it into multiple parts, then join it back together later?

How do i make sure my files don’t corrupt?

I am using Unix.

$ ls -l *.pkg
-rw-rw-r--  1 watashii watashii 648773362 Nov 28 18:01 largefile.pkg

Splitting the files

The following Unix command splits a large file into 50MB (52,428,800 bytes) pieces.  The output is a list of files named xaa, xab etc

$ split -b 52428800 largefile.pkg
$ ls -l x*
-rw-rw-r--  1 watashii watashii 52428800 Nov 28 18:01 xaa
-rw-rw-r--  1 watashii watashii 52428800 Nov 28 18:01 xab
...
-rw-rw-r--  1 watashii watashii 19627762 Nov 28 18:01 xam

Joining the files

To join the files together, we simply use the cat command over each file in ascending order:

$ cat x* > mergedlargefile.pkg

Validating the files

To validate the files, below are some suggestions. File compare it, diff it, run a checksum to compare it.

$ ls -l *.pkg
-rw-rw-r--  1 watashii watashii 648773362 Nov 28 18:01 largefile.pkg
-rw-rw-r--  1 watashii watashii 648773362 Nov 28 18:13 mergedlargefile.pkg

$ cmp  largefile.pkg  mergedlargefile.pkg
$ cksum  largefile.pkg
3332922138  648773362  largefile.pkg
$ cksum  mergedlargefile.pkg
3332922138  648773362  mergedlargefile.pkg
$ diff  largefile.pkg  mergedlargefile.pkg

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This post shows how to use PuTTY (Windows) to login to a remote server (UNIX) over SSH without password.

Step 1 – Setting up the remote server (UNIX)

Login to the remote server using the normal username and password.

Ensure that no-one but the user can access the .ssh path and authorized_keys file within the user directory

$ cd ~
$ chmod 700 .ssh
$ chmod 600 .ssh/authorized_keys

In the .ssh directory, we will create a public/private key-pair which will form the basis for authetication between the client and server.  Unix utility ssh-keygen will accept DSA or RSA (two commonly used key types) with a default 1024 bits key size.  Follow the prompts and accept the default filename, and leave an empty passphase to create your passwordless login.

$ ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (~/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Your identification has been saved in ~/.ssh/id_dsa.
Your public key has been saved in ~/.ssh/id_dsa.pub.
The key fingerprint is:
21:15:5d:13:68:42:10:46:bd:fa:bd:b6:7c:5d:64:f1

You should now have the key-pair files named id_dsa.pub and id_dsa.  Append the public key in authorized_keys as per below.

$ cat id_dsa.pub >> .ssh/authorized_keys

Step 2 – Generating the PuTTY private key (Windows)

You will need to transfer the id_dsa private key file on to the Windows client PC via SFTP (or various means).  Launch the puttygen Windows utility, go to [File > Load private key], and open your private key.

Save private key without a passphrase, as shown below, and name the file with a .ppk extension.

Step 3 – Setting up the PuTTY client (Windows)

So now you have a PuTTy-generated private key .ppk file, we can now use this to PuTTy-login to the UNIX server without needing a password.

Open your PuTTy Windows client, and before you connect your session, select the .ppk private key you generated under [SSH > Auth].

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netcool@sun61 [/opt/netcool] 688 % ps -ef|grep 6176
netcool 6176 1 0 Sep 12 ?  31:55 /opt/netcool/platform/solaris2/jre_1.5.0/bin/java -Xmx1024m -Xms256m -Djava.awt

So how can we show the entire command? The solution is to use the /usr/ucb/ps -auxxwww command:

netcool@sun61 [/opt/netcool] 689 % /usr/ucb/ps -auxxwww|grep -i 6176
netcool   6176  0.1 10.5610440428552 ?  R   Sep 12 31:55 /opt/netcool/platform/solaris2/jre_1.5.0/bin/java -Xmx1024m -Xms256m -Djava.awt.headless=true -Dnchome=/opt/netcool -Dngfhome=/opt/netcool/guifoundation -Dfile.encoding=UTF-8 -Dsun.jnu.encoding=UTF-8 -Dbase.directory=/opt/netcool -Dsm.props.directory=/opt/netcool/etc/sm -Djava.security.auth.login.config=/opt/netcool/guifoundation/conf/mach_jaas.config -Djava.endorsed.dirs=/opt/netcool/guifoundation/common/endorsed -classpath /opt/netcool/platform/solaris2/jre_1.5.0/lib/tools.jar:/opt/netcool/guifoundation/bin/bootstrap.jar -Dcatalina.base=/opt/netcool/guifoundation -Dcatalina.home=/opt/netcool/guifoundation -Djava.io.tmpdir=/opt/netcool/guifoundation/temp org.apache.catalina.startup.Bootstrap start

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Question: How can I list the true file and directory sizes on UNIX?

boadmin@nshost1>$ ls -la
total 12130522
drwxr-xr-x   5 boadmin  boadmin      512 Aug  4 14:30 .
drwxr-xr-x  31 boadmin  boadmin     1024 Aug  1 22:00 ..
drwxr-xr-x   5 boadmin  boadmin      512 May  7 05:48 DISK_1
drwxr-xr-x   3 boadmin  boadmin      512 May  7 05:47 DISK_2
drwxr-xr-x   3 boadmin  boadmin      512 May 31 14:02 sp3
-rw-r--r--   1 boadmin  boadmin  6207767040 Aug  4 14:33 sp3.tar

The short answer, use the following command: du -sh *

boadmin@nshost1>$ du -sh *
634M   DISK_1
152M   DISK_2
5.8G   sp3
5.8G   sp3.tar

du - is the disk usage utility on UNIX
 s - is to sum the files within the directory
 h - is the filesize in human readable format, megs, gigs, etc
 * - to group it on all elements in the current directory, or specify
any path here, or leave empty to summarize to one group

The long answer, use the following command and start reading: man du

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1. Commands
   crontab -e   # Edit (or create) the crontab file
crontab -l   # View the crontab file
crontab -r   # Remove the crontab file
2. Restrictions
   Crontab access is controlled with a cron.allow and a cron.deny file, listing the associated usernames.  If cron.deny exists, and cron.allow is missing, all users can use crontab.  If both missing then only root is allowed.
   whereis cron
3. Crontab file syntax
   The syntax contains 5 fields specifying the scheduling datetime values, and the last portion contains the Unix command to run.
   # +---------------- minute (0 - 59)
# | +------------- hour (0 - 23)
# | | +---------- day of month (1 - 31)
# | | | +------- month (1 - 12)
# | | | | +---- day of week (0 - 7) (Sunday=0 or 7)
# | | | | |
  * * * * * command to be executed
   On each of the 5 fields, 3 operators can be used to specify the datetime selection.
   # Comma (',') specifies a list of values, eg: "1,3,4,7"
# Dash ('-') specifies a range, eg: "1-3" or "1,2,3"
# Asterisk ('*') specifies all possible values for a field.
4. Crontab file example
   The following job lists the tmp directory structure and appends the output to a log file every minute.
   0-59 * * * *  ls -la /tmp >> /tmp/log.txt

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