25 Linux Shell Scripting interview Questions and Answers. by Pradeep Kumar · Published February 2, · Updated August 3, knowledge of Unix, Linux, SQL and other scripting language, which is quite true. various UNIX command interview questions asked to Java developers or. If you are preparing for Shell Scripting job interview, we will help you in clearing the interview through Wisdomjobs interview questions and answers page. Shell.
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Detailed answers to the Shell Scripting Interview Questions. Shell scripting is nothing but a series of UNIX commands written in a plain text file. We have selected expected 70 shell scripting question and answers for your interview preparation. Its really vital for all system admin to know. If you're looking for Unix Shell Scripting Interview Questions for Experienced or Freshers, . The answer to this question depends on the skills of a professional.
Boot Block: This represents the beginning of a file system. It contains bootstrap loader program, which gets executed when we boot the host machine. So, the information related to these files are stored in an Inode table. Data Block: This block contains the actual file contents. Lastly, it provides security using file encryption.
This Linux course is a great place to cover these. You can use the —d command, along with test commands, to see if a specified directory exists on the UNIX system. The —d command will then get UNIX to execute a specified test command if the directory exists.
Finally, fi will be executed last. Write the syntax for it. The FOR loops executes a command s if a condition is true. It will continue to execute the command s until the condition turns false. In UNIX, it will operate on items in a list, or a set of files, for example, and execute certain commands until it runs out of those items.
The syntax for the FOR loop is as follows: for var in a, b , c ….
What is swapping and paging? UNIX based operating systems automatically handle swapping and paging. Swapping and paging are processes that occur when the operating system is managing system memory.
Every process in UNIX based systems has individual segments. An area of the disk is treated as the swap space where these segments are stored temporarily as long as a process needs them. Consider a reference book, for example. That is both almost impossible and extremely inefficient.
A book is comparable to a process in UNIX. At any given time, there are several books that UNIX is reading. However, UNIX only takes a few pages from a book at one time, as needed.
This is known as paging. Sometimes UNIX sends the entire book, with all its pages, back to the memory- this is known as swapping. This happens when the work load is really heavy. Paging is more efficient if UNIX is running a large number of processes at one time.
Question 3. How Do You Remove Recursively? Question 4. Question 5. Question 6. Question 7.
Question 8. Question 9. Question What Is Shell Scripting? Shell scripting is used to program command line of an operating system. Shell Scripting is also used to program the shell which is the base for any operating system. Shell scripts often refer to programming UNIX.
Also this script is used by companies to develop their own operating system with their own features. There are many advantages of shell scripting some of them are, one can develop their own operating system with relevant features best suited to their organization than to rely on costly operating systems.
Software applications can be designed according to their platform. There are many disadvantages of shell scripting they are. Major disadvantage of using shell scripting is slow execution of the scripts. This is because for every command a new process needs to be started. This slow down can be resolved by using pipeline and filter commands. A complex script takes much longer time than a normal script.
There are many situations where typing errors can prove to be a real costly effort. For example a single extra space can convert the functionality of the program from deleting the sub directories to files deletion. Explain About Return Code?
Return code is a common feature in shell programming. These return codes indicate whether a particular program or application has succeeded or failed during its process. Variables can be defined by the programmer or developer they specify the location of a particular variable in the memory.
There are two types of shells they are System variables and user defined variables.
System variables are defined by the system and user defined variables are to be defined by the user small letters. Explain About Gui Scripting? Graphical user interface provided the much needed thrust for controlling a computer and its applications.
This form of language simplified repetitive actions. Support for different applications mostly depends upon the operating system. These interact with menus, buttons, etc. Explain About Echo Command? Echo command is used to display the value of a variable. These are known as standard input, output and error.
These are categorized as 0, 1 and 2. Each of these functions has a particular role and should accordingly functions for efficient output. Any mismatch among these three could result in a major failure of the shell. Explain About Sourcing Commands? Sourcing commands help you to execute the scripts within the scripts. For example sh command makes your program to run as a separate shell. This is an important command for beginners and for special purposes.
Explain About Debugging? Shell can make your debugging process easier because it has lots of commands to perform the function.
For example sh —n command helps you to perform debugging. It helps you to read the shell but not to execute it during the course. Similarly sh —x command helps you by displaying the arguments and functions as they are executed. Explain About Login Shell? Login shell is very useful as it creates an environment which is very useful to create the default parameters. It consists of two files they are profile files and shell rc files.
These files initialize the login and non login files. Environment variables are created by Login shell. Explain About Non-login Shell Files? The non login shell files are initialized at the start and they are made to run to set up variables. Parameters and path can be set etc are some important functions.
These files can be changed and also your own environment can be set.
These functions are present in the root. It runs the profile each time you start the process. Explain About Shebang? Shebang is nothing but a sign followed by an exclamation.
This is visible at the top of the script and it is immediately followed by an exclamation. To avoid repetitive work each time developers use shebang. After assigning the shebang work we pass info to the interpreter. Explain About The Exit Command?
Every program whether on UNIX or Linux should end at a certain point of time and successful completion of a program is denoted by the output 0. If the program gives an output other than 0 it defines that there has been some problem with the execution or termination of the problem. Whenever you are calling other function, exit command gets displayed. Explore About Environment Variables? Environment variables are set at the login time and every shell that starts from this shell gets a copy of the variable.
When we export the variable it changes from an shell variable to an environment variable and these variables are initiated at the start of the shell.