Linux Tips & Tricks

Example: Sample users name: dummy1, dummy2, dummy3, dummy4 and dummy5 for counter in {1..5}; do echo "dummy$counter" | passwd...

Example 1: To delete the users: dummy1, dummy2, dummy3, dummy4 and dummy5 for  counter in {1..5}; do userdel dummy$counter; done It ...

Example 1: NOTE:   {1..5} syntax will not work in certain shell. But it will work definitely in bash. Example 2: cat > u...

In Solaris, Solaris grep will not provide recursive option -r to search a pattern recursively. But solaris provides another command called g...

This method works perfectly in any shell. NOTE: $$ holds the process id of current shell. [penguin@cheetah:/home/penguin]#ps | grep -i `...

PIPE: Pipe is a way of passing data from standard output of one process to standard input of another process. Filter: It is a program...

ls -1A | grep '^\.' Eg: [vjsujay@cheetah:/home/vjsujay]#ls -1A | grep '^\.' .profile .recently-used .sh_history .so...

Question 1: How to update an existing tarball contents with newfile(s)? Answer: We have to use the function ‘u’ to update newfile(s) t...

Question: How to pass large number of files as an argument for tar archive creation? Answer: Using the option ‘I’   From Solaris M...

Question: To extract the desired file/directory from a tarball Answer:   Pass the desired file/directory as an extra argument to the ...

Question: Default shell of the logged in User Answer: There are many ways to find the default shell. a)       By checking the la...

As soon as we press the enter key after the command, the below sequence will be followed. 1.  Check alias and then execute the command(she...

Giving 777 to any directory in UNIX or Linux or UNIX based Operating System is a potential security risk. Because if a directory contains 77...

1.)Question: How to find the number of CPU, CPU Speed and RAM size? Ans: prtdiag Command Name: prtdiag Purp ose: To display the...

There are multiple ways to find whether a file is empty or not. Please see few examples below, volcano@volcano-laptop:~/shellscript$ ls -l...

volcano@volcano-laptop:~/shellscript/empty$ cat testempty hi first line above line is empty hi dude above line is empty volcano@volca...

Control-m characters will get appended to a file when a file is transferred from windows to UNIX machine. There are multiple ways it can be ...

There might be several ways to remove files starting with first character as - minus. But i am providing 3 solutions below. 1. $ rm ./-filen...

Internal Unix commands are built with the shell and hence it will run in the same shell. eg: cd External Unix commands will start a new shel...

To run a script from anywhere inside UNIX directory, you need to include the script absolute directory in the PATH variable. After that with...

If interactive login-shell or non-interactive login shell with --Login option is started, it will start reading & executing in the order...

.profile will be read, whenever login-shell is started .bashrc will be read, whenever new interactive shell(not a login shell) is started

1. Put all the required filenames in a file 2. tar all the files 3. gzip the tar file eg: vjsujay@gmail.com$ ls *.html > filelist vjsuja...

vjsujay@home$ ls -lA "pipeline symbol" grep '^d' drwxr-s--- 2 n0160429 ccipadm 512 Jul 21 00:17 .temp drwxr-s--- 2 n01604...

1. [ conditional check ] -> Variables used in the conditional check should have value, otherwise exception will be thrown during the exec...

In two ways we can do the command substitution. 1.) Using backquote: `` 2. Using dollar sign and parenthesis: $() eg: vjsujay@home $ echo ...

By using "script" command, you can keep track of Executed Commands and its output. Definition: The script command will keep a tran...

1. Executing the Shell Script file as a command in the Shell Prompt vjsujay@linuxdemon$sample.sh 2. Executing the Shell Script file using s...

$ ls -l thisismytestfile -rw-r--r-- 1 Ajay None 13 Apr 17 03:22 thisismytestfile Ajay@intel ~ $ cp thisismytestfile{,.bk} Ajay@intel ~ $ ls ...

:>filename If the filename already exists,the file will be truncated to ZERO byte file else a new file with ZERO byte will be created. Ex...

By using anonymous here document, we can comment multiple lines in a shell script for debugging purposes. eg: : echo "Not in the Scope ...

The command syntax is ${#string} Example: linuxdemon$lindem="linux demon" linuxdemon$echo ${#lindem} 11 Explanation: 1.Assigning t...

I am going to give the code in shell script for ftp automation. ftp -n servername/serverIP user giveusername givepassword Any ftp comma...

Temporary Mounting: After the reboot of your system, you need to again execute the mount command to mount the win partition in Linux. 1.You...

I am giving a simple shell script, for renaming a group of files in the current directory.In the script, i have renamed all .jsk files to .t...