Red Hat Linux Essential

I want to write here with some importance Command of Red Hat Linux Essential. If you follow this command you can make yourself as a Linux Essential experts. I believe that you are able to improve your knowledge in Linux.

Follow The bellow Command ...

  Red hat Essential  

#startx

#vim /etc/issue

   Welcome!

#passwd student

#su - student

#id student

#date

#date 10 21 05 42 2011

#cal 5 2010

#whatis cal

#cal --help

#man -K|k keyword

#man print

#info vim

#foo -y -abc one.txt two.txt

#pwd

#ls -l /lv1

#ls -la /tmp

#ls -ld /etc

#cd

#ls -lR /home/users

#cd ..

#cd /etc/system

#cd -

#cp /etc/passwd /tmp

#cp -r /etc/ /tmp

#cp /pearctice/* /tmp

#cp -r /practice/* /tmp

#cp -rpv /etc/sysconfig /backup/sysconfig12102011

#mv /practice /tmp

#touch /newfile

#touch {report,graph}_{jan,feb,mar}

#rm -rf /tmp/newdir (dir with file)

#rmdir /tmp/practice (empty dir)

#mkdir /test

#mkdir -p /practice/new/user

#file /etc/passwd (prints file type)

#chown root /practice/new

#chown -R root /practice/ (recursively)

#chown root:marketing /practice

#chgrp accounting /practice/new

#chgrp -R accounting /practice/

#chmod u|g|o| +|-|= r,w,x,s,t /practice

#chmod u+w /practice

#chmod o+t /practice

#chmod 764 /practice

#echo ?o*

#history

#!! (repeats last cmd)

#!ca (repeats command begins with "ca")

#!232 (repests command with history number)

#vim .bashrc

   export HISTCONTROL=ignoreboth

   alias c='clear'

#alias c=clear

#echo file {1,2,3}

#echo "this system's name is $(hostname)" (command expansion)

#echo "this system's name is `hostname`" (command expansion)

#vim /script

  #!/bin/bash

   /bin/echo hello

#chmod u+x /script

#vim /testscript

 #!/bin/bash

   cp -av /etc/sysconfig /backup/sysconfig-$(date '+%y%m%d')

  echo "back up of /etc/sysconfig completed at: $(date)"

#find /etc -name passwd

#find /etc -name passwd > /redirect

#find /etc -name passwd >> /redirect

#find /etc -name passwd &>> /redirect

#ls -l /etc | tr 'A-Z ' 'a-z'

#ls -l /etc | less

#echo "test mail" | mail -s test user1@localhost

#echo "test printer" | lpr -P printer1

#ls -lR /etc | tee stage1.out | sort | tee stage2.out | sort -r | tee stage3.out | less

#tr 'A-Z' 'a-z' < .bash_profile

    or

#cat .bash_profile | tr 'A-Z' 'a-z'

#mail -s "test" user1@localhost <<end

      hi susan

      please call me

      brad

      end

## looping#####

#vim /bin/script

   #!/bin/bash

     for n in {1..10}; do

     ping -c2 192.168.0.$n

     done

#chmod u+x /bin/script

####Test all host at a time###### 

#vim /bin/script1

   #!/bin/bash

     for n in {1..10}; do

     host = 192.168.0.$n

     ping -c2 $host > /dev/null

     if [ $? = 0 ]; then

        echo "$host is success"

    else

       echo "$host is failed"

    fi

    done

#chmod u+x /bin/script

#####shutdown all workstation from server

#vim /bin/script1

   #!/bin/bash

     for n in {1..10}; do

     host = 192.168.0.$n

     ping -c2 $host > /dev/null

     if [ $? = 0 ]; then

        ssh root@$host reboot/poweroff

    else

       echo "$host is blocked"

    fi

    done

#### conditional exicution#####

#!/bin/bash

for x in $(seq 1 10); do

echo adding testuser$x

(

echo -ne "testuser$x\t"

useradd testuser$x 2>&1 > /dev/null && passwd testuser$x

) >> /tmp/userlog

done

echo 'cat /tmp/userlog to see new paswrds'

#cat /etc/passwd 

#less /etc/paswd

 q to quit

#cat -b /proc/meminfo (with number of each line)

#cat -A /proc/meminfo (show all character,including non printing)

#head /etc/passwd

#head -n 15 /etc/passwd

#tail -n 3 /etc/passwd

#tail -f /var/log/cron

#tail -f /var/log/messages

#grep 'user1' /etc/passwd

#date --help | grep year

#grep -n user1 /etc/passwd (prints the number of matches)

#ps ax | grep init (shows all process and grep init strings)

#grep root /etc/passwd | cut d : -f 7 (cut practice)

#cut -f3 -d: /etc/passwd

#wc /etc/passwd

#wc -m /etc/passwd (bytes)

#wc -l /etc/passwd (only lines)

#wc -w /etc/passwd (only words)

#sort -r /etc/passwd

#cut -f7 -d: /etc/passwd | sort | uniq (uniq)

#diff -u /practice/file /practice/file1 > file2.patch

#patch -b /practice/file1 file2.patcch

#aspell check /newfile

#aspell list < /newfile

#look wh /practice/file (looks for word begins with wh string)

what

why

#sed 's/cat/dog/gi'

#sed '1,50s/cat/dog/gi'

#sed '/digby/,/duncan/s/cat/dog/gi'/practice/file1

#sed -e 's/cat/dog/gi'-e 's/cow/goat/gi'

#vim /practice/file

 insert mode

  I (inser at begining of line)

  A(append to end)

  O(insert a new line above)

  o(insert a new line below)

 command mode

  u,U ctrl+r

#vim .vimrc

  :set number

#/sbin/ifconfig eth0

#/sbin/ifup eth0

#/sbin/ifdown eth0

#system-config-network

#vim /etc/sysconfig/network-script/ifcfg-eth0

#system-config-printer

#   /etc/cups/printer.conf

#lpr -P printer1 -#3 /file1 (3 copy)

#lpq

#lprm 6

#lpstat -a (list configured printer)

#system-config-date

#date 10 21 05 42 2011

#ps -ax | grep init

#ps -U root

#pgrep -G accounting

#pidof cupsd

#kill 2372 (if ctrl+c or 'term' not working)

#kill -term 2372

#man 7 signal

#nice -n 5 cat

#renice 5 -p pid

#top

#jobs

#bg 4

#fg 6

#at now+5min

  cat /etc/passwd

  ping -c3 server.example,com

  ctrl+d

#at -l

#at -c 7

#crontab

    25 15 24 07 1,3,5 (0-6)

  min hour day month week

#crontab -u testuser

#crontab -r; crontab -l (remove cron)

#date > /logfile | cat /logfile

#who | wc -l >> /logfile

#ping -c2 192.168.0.12 &> /dev/null

#echo $? (0 success,1-255 failure)

#vim .bashrc

  alias c='clear'

#vim /bin/script2

  #!/bin/bash

  read -P "enter server1 values:" value1 value2

  echo "value1 is $value1"

  echo "value2 is $value2"