UNIX Commands Interview Questions

In this Post, We will discuss most frequently asked UNIX Commands Interview Questions.

Table of Contents

Common Commands:

Pwd – Present working directory.
clear – clear the screen.
ls – listing of the files.
ls -l – Listing of the files with numbers.

Folder Commands:

mkdir dirName – To create the directory
mkdir -v dirName – To create the directory with verbose message.
./.. — two folder back.
mv oldDirName newDirName —- Rename the file
rmdir -v DirName – removing file.

Working with directory:

mkdir Hello{1..10} – it will create 10 folder Hello1, Hello2……Hello10

rmdir Hello* — Remove folder which start from Hello name.

Create File using Commands:

touch filename – Create a blank file

cat > filename [Press Enter] —– Enter data inside the file.

data…. [Enter]

Press Ctrl+C

Check the details: – ls -l

Display files in folder: – Use of ls command)

ls -l
ls -la – also show hidden file.
ls -lat – Files showing in sorted order of creation. [l for listing order, a for all and t for sorted in time.]
ls -t – Display in sorted order of time.
ls -latr – display in reverse order of time.

UNIX Commands Interview Questions of CAT command: –

cat Filename – Display content of the file.
cat -n filename – display content of file with line number.
cat old filename > new Filename – where u want to copy content of old file. [This will delete the previous data of new file in which u want to copy content]
cat oldfilename >> new file name – copy data in append
cat file1 file2 > file3 – merge multiple file data into new a file.
tac filename – show reverse order of content in file.

View Content of File: –

Display few lines from the top of the file (default 10) – head file name
Control lines what you line want to print – head 20 fileName
Display bottom lines – tail filename

Search Data in File – Grep (Global regular expression parser) Command

grep “Content” filename

Search data in more than one file: –

Grep “Content” fileName1 fileName2

Search data in all files: –

Grep “Content” *.*

Search data by ignoring case: –

grep -I Content *

Use of Cat Commands:

Creating the new file

Display content of the file

Concatenating more than one file

Appending data to the existing file

Use of cp Command:

Copy contents from a file to another file(source to destination)

Use of mv Command:

Renaming a file(changing name of the file)

Renaming a directory

Moves files from one directory to another directory

Use of rm Command :

Delete/remove a file or directory (only if directory is empty).