‘read’ command reads in data from the terminal (using keyboard). The read command takes in whatever the user types and places the text into the variable you name.
Example is shown below
# vi /tmp/test.sh
#!/bin/bash
echo ‘Please enter your name’
read name
echo “My Name is $name”
# ./test.sh
Please enter your name
LinuxTechi
My Name is LinuxTechi
What Is The Use Of Continue Command In Shell Scripting?
The continue command is identical to break command except it causes the present iteration of the loop to exit, instead of the entire loop. Continue command is useful in some scenarios where error has occurred but we still want to execute the next commands of the loop.
What Is Shell Script And Why It Is Required?
A Shell Script is a text file that contains one or more commands. As a system administrator we often need to issue number of commands to accomplish the task, we can add these all commands together in a text file (Shell Script) to complete daily routine task.
What Is The Default Login Shell And How To Change Default Login Shell For A Specific User?
In Linux like Operating system “/bin/bash” is the default login shell which is assigned while user creation. We can change default shell using the “chsh” command.
Example is shown below
# chsh <username> -s <new_default_shell>
# chsh linuxtechi -s /bin/sh
The do-while statement is similar to the while statement but performs the statements before checking the condition statement.
The following is the format for the do-while statement
do
{
statements
} while (condition)
 |
| NetApp Most Frequently Asked Latest Linux Interview Questions Answers |
How To Define Functions In Shell Scripting?
A function is simply a block of of code with a name. When we give a name to a block of code, we can then call that name in our script, and that block will be executed.
Example is shown below:$ disk usage () { df -h ; }
How To Use Bc (bash Calculator) In A Shell Script?
Use the below Syntax to use bc in shell script.
Variable=`echo “options; expression” | bc`.
Like the for loop, the while loop repeats its block of commands a number of times. Unlike the for loop, however, the while loop iterates until its while condition is no longer true.
The basic syntax is
while [ test_condition ]
do
commands…
done
How To Make A Shell Script Executable?
Using the chmod command we can make a shell script executable.
Example is shown below
# chmod a+x myscript.sh
What Is The Use Of “#!/bin/bash” ?
#!/bin/bash is the first of a shell script , known as shebang , where # symbol is called hash and ‘!’ is called as bang. It shows that command to be executed via /bin/bash.
What Is The Syntax Of For Loop In Shell Script?
Basic Syntax of for loop is given below
for variables in list_of_items
do
command1
command2
….
last_command
done
How To Debug A Shell Script?
A shell script can be debug if we execute the script with ‘-x’ option ( sh -x myscript.sh). Another way to debug a shell script is by using ‘-nv’ option (sh -nv myscript.sh).
How Compare The Strings In Shell Script?
Test command is used to compare the text strings. The test command compares text strings by comparing each character in each string.
What Are The Special Variables Set By Bourne Shell For Command Line Arguments?
The following table lists the special variables set by the Bourne shell for command line arguments.
Special Variables: Holds
$0: Name of the Script from the command line
$1: First Command-line argument
$2: Second Command-line argument
…..
…….
$9: Ninth Command line argument
$#: Number of Command line arguments
$*: All Command-line arguments, separated with spaces
How To Test Files In A Shell Script?
Test command is used to perform different test on the files. Basic test are listed below
Test: Usage
-d file_name: Returns true if the file exists and is a directory.
-e file_name: Returns true if the file exists.
-f file_name: Returns true if the file exists and is a regular file.
-r file_name: Returns true if the file exists and have read permissions.
-s file_name: Returns true if the file exists and is not empty.
-w file_name: Returns true if the file exists and have write permissions.
-x file_name: Returns true if the file exists and have execute permissions.
‘unset’ command is used to de-assign or unset a variable.
Syntax is shown below
# unset <Name_of_Variable>
How To Perform Arithmetic Operation?
There are two ways to perform arithmetic operations
Using expr command (# expr 5 + 2).
Using a dollar sign and square brackets ( $[ operation ] ) Example : test=$[16 + 4] ; test=$[16 + 4].