LINUX Clouds

$ ls -A .bash_history .bash_logout .bash_profile .bashrc archive check-orders.sh orders.txt The filenames can be printed in color to show the kind of file they are.The colors are defined in a file /etc/DIR_COLORS.You can customize the colors using a .dir_colors file in your own directory.The format of the file is described in the /etc/DIR_COLORS file. To display the files without color and with symbols instead, use the --color and --classify (or -F) switches. (On most Linux distributions, this feature is turned on using aliases.) $ ls --color=never --classify archive/ check-orders.sh* orders.txt The –classify symbols are directories (/), programs (*), symbolic links (@), pipes (|), and Unix domain socket files (=).These symbols are not a part of the name:They are hints as to the type of file. In this example, archive is a directory and check-orders.sh is a program. Another very important switch is --hide-control-chars (or -q). Linux filenames can contain any character, even control cha...

We can extract our tar archived file to our required destination with using copy and all in single shot. cd /to/where/archived/file.gz tar -xzf filename.gz -C /destnation/dir/ ; cd /destination/dir/ it will extract the file in the path given like /destination/dir/ and cd will change your dir to that dir. e.g cd Downloads tar -xzf zabbix-2.6.gz -C /opt/ ; cd /opt/zabbix-2.6/ pwd /opt/zabbix-2.6

#pwd;echo "Hello World" [davsingh@noisecover-dr Scripts]$ ls -l && pwd ---> If first run then second will execute otherwise it will not work total 16 -rw-r--r-- 1 davsingh users 0 Jan 21 12:52 a -rw-r--r-- 1 davsingh users 0 Jan 20 14:18 ABC.txt.txt -rw-r--r-- 1 davsingh users 0 Jan 21 12:52 b -rw-r--r-- 1 davsingh users 0 Jan 21 12:52 c -rw-r--r-- 1 davsingh users 0 Jan 20 11:29 junk1.data.txt.txt -r--r--r-- 1 davsingh users 5956 Jan 20 11:29 passwd.txt.txt drwxr-xr-x 2 davsingh users 4096 Jan 21 12:58 test -rwxr-xr-x 1 davsingh users 166 Jan 20 14:21 upper-lower.sh.txt /home/davsingh/Scripts [davsingh@noisecover-dr Scripts]$ cat abc && pwd ----> first fails so second command not work cat: abc: No such file or directory [davsingh@noisecover-dr Scripts]$ cat abc || pwd --> If first fails then second runs cat: abc: No such file or directory /home/davsingh/Scripts

#cd /tmp #echo $? 0 --> it means successful we have 0-255 exit codes where "0" is only for successful. [root@noisecover-dr ~]# pzw -bash: pzw: command not found [root@noisecover-dr ~]# echo $? 127 --> it is reserved for command not found. 126--> permission issue

#alias df='df -TH' [root@noisecover-dr ~]# df Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/sys-root ext3 241G 31G 198G 14% / /dev/sda1 ext3 104M 19M 80M 19% /boot tmpfs tmpfs 2.1G 0 2.1G 0% /dev/shm /home/davsingh/Desktop/rhel-server-5.5-i386-dvd.iso iso9660 3.2G 3.2G 0 100% /rhel5.5/ISO #unalias df [root@noisecover-dr ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/sys-root 234410632 29446100 192864948 14% / /dev/sda1 101086 18176 77691 19% /boot tmpfs 2022912 0 2022912 0% /dev/shm /home/davsingh/Desktop/rhel-server-5.5-i386-dvd.iso 3038672 3038672 0 100% /rhel5.5/ISO

# vi /etc/bashrc alias df='df -TH' --> paste at last for user specific setting add in /home/username/.bashrc

[davsingh@noisecover-dr test]$ touch test{1,2,3} {a,b,c} [davsingh@noisecover-dr test]$ ls a b c test1 test2 test3 [davsingh@noisecover-dr test]$ rm -rf test* [davsingh@noisecover-dr test]$ rm -rf {a,b,c} [davsingh@noisecover-dr test]$ touch test{1,2,3}{a,b,c} [davsingh@noisecover-dr test]$ ls test1a test1b test1c test2a test2b test2c test3a test3b test3c

#answer=ind [davsingh@noisecover-dr Scripts]$ set | grep -e "answer" -e "lastname" answer=ind lastname=singh #use the unset command [davsingh@noisecover-dr Scripts]$ unset answer [davsingh@noisecover-dr Scripts]$ set | grep -e "answer" -e "lastname" lastname=singh [davsingh@noisecover-dr Scripts]$ set | grep answer [davsingh@noisecover-dr Scripts]$

[davsingh@noisecover-dr Scripts]$ set | grep -e "answer" -e "lastname" answer=ind lastname=singh For not equal to [davsingh@noisecover-dr Scripts]$ seq 10 | grep -v -e "1" -e "5" 2 3 4 6 7 8 9

[davsingh@noisecover-dr Scripts]$ read test davinder singh [davsingh@noisecover-dr Scripts]$ echo $test davinder singh [davsingh@noisecover-dr Scripts]$ read firstname lastname davinder singh [davsingh@noisecover-dr Scripts]$ echo $firstname davinder [davsingh@noisecover-dr Scripts]$ echo $lastname singh [davsingh@noisecover-dr Scripts]$ echo $firstname $lastname davinder singh

#script to change charaters from upper to lower #!/bin/bash echo $0; for i in `ls -A` do newname= echo $i|tr A-Z a-z echo $i $newname mv $i $i.txt done ~

It is called the Shebang rotation #which bash /bin/bash #sh script_name.sh ---> here we no need to mention !/bin/bash line in script but we want to give as below then we reuired the line so that it can understand it will be bash #./script_name more details check the below URL http://en.wikipedia.org/wiki/Shebang_%28Unix%29

#!/bin/bash echo "Hello World"

cut -f1 -d: passwd |sort|uniq it will cut the first field in passwd file & sort with according to alphabets & only show the unique names. cut -f3 -d: passwd |sort -n|uniq it will cut the 3rd field in passwd file & sort according to the numeric numbers & show the unique numbers only.

echo $0 for example [davsingh@noisecover-dr Scripts]$ ksh $ echo $0 ksh $ exit [davsingh@noisecover-dr Scripts]$ echo $0 -bash

mount -o loop /home/davsingh/Desktop/rhel-server-5.5-i386-dvd.iso /rhel5.5/ISO/

If we have a file with 1-300 lines are there & need to create separate files for 20 lines... means need to create 15 files to separate the 20 lines in each file. mkdir test cd test split -l 20 ../server.txt bash-3.2$ ls -l total 128 -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xaa -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xab -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xac -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xad -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xae -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xaf -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xag -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xah -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xai -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xaj -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xak -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xal -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xam -rw-r--r-- 1 davsingh staff 500 Jan 10 15:21 xan -rw-r--r-- 1 davsingh staff 500 ...