awk notes - Copyright © 1995 - 2002 John Meister

wagoneers.com


 note: most of these commands are for HP-UX 


 

 things to do with awk  

 check user id's and home directories 
cat /etc/passwd | awk -F: '{print $3" " $6}' | sort > sorted.pass.3.6

 sort a password file in NIS 
cat /var/yp/passwd | awk -F: '{print $3"  "$6"  "$1}' | sort

 look for a process and kill it 

# looking for specific string in process, e.g. dial (from a failed ppp)
ps -ef | grep dial | awk '{print "kill " $2}' 

IF IN A SCRIPT (pass it via a file):
ps -ef | grep dial | awk '{print "kill " $2}' > /tmp/killproc
sh /tmp/killproc 



 SET DISPLAY in .profile (tested on Sun and HP) 
who am i -R | tr -d [\(-\)] | awk '{print $NF}' | grep -v :0 | \ 
 	awk '{print "export DISPLAY="$1 ":0"}' > /tmp/setdisplay
. /tmp/setdisplay
/usr/bin/env | grep DISPLAY

NOTE:  ALWAYs look at Display setting, especially if you're moving
around and logging in and through other systems!  When using xterm
or other GUI tools, always launch with an ampersand (&) at the end
so you're able to kill it from jobs.  (jobs lists the processes
running in the background, kill %# - #=job number)

(HP-UX 11i on an 800 series wanted env fully resolved /usr/bin/env)


 test login against current userid 
if [ `who am i | awk '{print $1}'`=`whoami`] 
then 
blah;blah 
exit;exit 
fi 
 

 more real life examples 

to change user "luser"'s group from "lgroup" to "othergrp" 
 -----------------------------------------------------
root@server [/home/files]

ll | grep luser | grep lgroup | awk '{print "chown luser:othergp" " " $9}' > list
chmod 700 list
./list





 test to force an su login 
case `/usr/bin/who am i | awk '{ print $1 }'` in
    userid)  if [ `/usr/bin/who am i | awk '{ print $1 }'` = `/usr/bin/whoami` ]
                then
                echo "################no#login#########################"
                exit;exit
                fi;;
esac


NOTE:  userid is login name that can not login directly



 root-#->HOW-TO-CLEAR-A-USER 
# handy way to clear dead sessions and ALL activities of a user
#  or a process.  Puts the kill on each line.
#
# ps -ef | grep userid > nuke.userid
# cat nuke.userid | awk '{ print "kill -9 " $2 }' > nuke
# more nuke
# sh nuke

# w

 to view a specific field
awk -F: '{ if ($2 == "") print $1 }' /etc/passwd
awk -F: '{ if ($3 == 0) print $1}' /etc/passwd


 find all files and other stuff

/usr/bin/find / -user root -perm -4000 -print | tee -a /root/suid.files

(also: can use ncheck to check for suid  or
   /dev/kmem to check perms
   /etc/securetty - restricts root login
   COPS - Computer Oracle & Password System
   strings may be used to view files 
   Tripwire) 

 an odd ball task solved by AWK 
THE PROBLEM:   
     I had a bunch of email addresses from a recent microslop virus problem
   that I needed to sort out onto one line each.   I tried to replace the
   comma separator with a newline using sed within vi, and at the command
  line with little success.  Didn't have my Perl notes with me, so, I worked it
  this way, convoluted as it may be... ;) 

 the solution

cat emails | awk -F , '{print $1}' > email1
cat emails | awk -F , '{print $2}' > email2
cat email2 >> email1
mv email1 list-o-emails

wagoneers.com

Select pages from WAGONEERS.COM:

the Full Size Jeep decal! © 1998-2000 John Meister

Buy this FSJ decal... ...use PayPal to pay for it!

a viable option to bloated and unstable code

AMSOIL synthetic lubricants and filters
(please use customer #283461)

Independent Lifetime Dealer John Meister - customer #283461 - since 1983

Shop AMAZON.com from wagoneers.com!

Search:
Keywords:

"Join the fight against spam (UCE)! Eliminate spam!"

Washington State has a $500 fine for "spam"
(unsolicited commercial email)!

read the Bible