Unix and Linux Tips

Rabu, 21 Desember 2011

Unix Tip: KEEP THAT USER OUT!

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3603 - December 21, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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KEEP THAT USER OUT!

Ever get into one of
those pesky admin wars
or need to keep the
developers off of your
system for a few minutes
without taking the system
to single user mode?

This nasty little script
will do the trick.

[root@foo /]# while true
> do
> kill -9 $(ps -aux |grep username | awk '{ print $2 }' )
> sleep 2
> done

This can make you the life
of the party (At work)

Don Cooley
Unix Systems/Security Admin
Wellogix Inc.
dcooley@wellogix.com

This tip generously supported by: dcooley@wellogix.com

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Selasa, 20 Desember 2011

Unix Tip: GETTING IPs FROM IFCONFIG

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3602 - December 20, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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GETTING IPs FROM IFCONFIG

You can use ifconfig to lookup
IP addresses bound to your box.
If you do not want to search the
output from ifconfig, use the
following command to get just
the IP listing.

ifconfig | awk '/inet/{print $2}' | awk -F: '{print $2}'

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Senin, 19 Desember 2011

Unix Tip: PING THE HOST TABLE

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3601 - December 19, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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PING THE HOST TABLE

There's no need to grep and
pipe the output into awk
(you can "grep" with awk.)

awk '/^[0-9]/{print $1}' /etc/hosts |xargs -l ping -c 1 $1

This tip generously supported by: bmaclean@silverplatter.com

And another:

awk '/^[^#]/ {system("ping -c 1 "$1)}' < /etc/hosts

This tip generously supported by: maddox@xmission.com

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Minggu, 18 Desember 2011

Unix Tip: USES FOR AWK

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3600 - December 18, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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USES FOR AWK

If you have a server
with alot of filesystems
on it (oracle/SAP
environments) then this
little awk command can
come in useful. It can
obviously be used in many
other situations also. In
this example, the file
structure is /oracle/PRD/xxxx.

awk '/PRD/{ print "umount " $3 }' /etc/vfstab | /sbin/sh

If you run it without
piping it to 'sh', then it
will show you what the command
will do. You can replace the
'umount' with whatever command you
like. It's a quick and easy though.

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Sabtu, 17 Desember 2011

Unix Tip: PERL FIND AND REPLACE

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3599 - December 17, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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PERL FIND AND REPLACE

In UNIX environment, the
following combination of perl
and find will serch for a
particular file and replace
the occurence of a particular
string with another string in
that file. This will also
work for multiple files and
directories. The find
command finds the file and
the perl script replaces
old string with the new one.

At the command prompt give
this command:

# perl -pi -e 's/<old string>/<new string>' `find . -name "<file name>"`

NB: Perl should be in the
path and the general regular
expression rules apply while
using special characters
for eg / or .

This tip generously supported by: pandpr@dh.cit.alcatel.fr

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Jumat, 16 Desember 2011

Unix Tip: BE ALARMED

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3598 - December 16, 2011

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BE ALARMED

Name the following script
alarm. Make it executable
and them invoke it as:

% alarm 10 "Time for tea"

After 10 seconds machine will
echo Time for Tea
and beep five times.....

---------------

#! /usr/bin/ksh
# alarm program
# displays a message at
if [ $# -ne 2 ]
then
echo "USAGE : $0 seconds message"
exit 1
fi

time=$1
mesg=$2
signal_alarm()
{
sleep $time
banner $mesg
for i in 1 2 3 4 5 6 7 8 9
do
if [ $i -eq 2 -o $i -eq 4 -o $i -eq 6 -o $i -eq 8 ]
then
sleep 1
else
tput bel
fi
done
}

case $1 in

[0-9][0-9][0-9] | [0-9] | [0-9][0-9] )signal_alarm &;;
*)echo Seconds range is from 0 to 199;;

esac

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Kamis, 15 Desember 2011

Unix Tip: NUMBERING A FILE

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3597 - December 15, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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NUMBERING A FILE

Ever want line numbers
appended to a file. Here
is a short script.

awk '{no=no+1; printf"%d : %s", no, $0}' filename > filename.out

Another shorter but not
necessary elegant method
is:

grep -n . filename > filename.out

filename is the original file
filenmae.out is the file with
line numbers appended at the
beginning of each line

This tip generously supported by: pradeep@unixguru.zzn.com

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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