Grep c ^$ <filename>
How to remove Empty lines form a given file?
Grep v ^$ filename > temfilename
Mv tempfilename filename
What is pattern to search 4 digit word in a file?
Grep \<[0-9] [0-9] [0-9] [0-9]\> filename
What is pattern to search the line having only three characters?
Grep ^ $ filename
What is pattern to display lines ending with $ character in a given file?
Grep \$$ filename
How to display 2 and 4 th fileds from a given file if the delimetr is :?
Cut d: f 2,4 filename
How to display unique lines from a given file?
Sort u filename
How to eliminate completely duplicate lines from a given file?
Uniq u filename
How to remove all duplicate lines from a file?
Uniq u filename > tempfilename
Mv tempfilename filename
How to delete hello word from a given file?
Sed s/hello// filename
How to compare two files are same or not?
Cmp
How to display the first 10 lines from a file?
Head -10 filename
Write a one line command to convert all the capital letters of a file "test" into lower case?
cat filename | tr "[A-Z]" "[a-z]"
The pipeline to list the five largest files in the current directory is
ls -l | tr -s ' ' | sort -t ' ' -fnr +4 -5 | head 5
The pipeline to find out the number of times the character
? occurs in the file is
tr -dc '?' < file | wc -c ( Delete
all the characters except ? and then make a word count.)
How to count total no. of users working in the system?
Who | wc l
How to display the lines from 5 to 10 from a given file?
Head -10 filename | tail +5
What will be output of following command?
echo Tecnosoft | wc c
9
What is the default umask?
022
What is the default permission for File & Directory?
The default privileges for file : 644
The default privileges for directory : 755
What UNIX command will control the default file permissions when files are created?
Umask
Explain the read, write, and execute permissions on a UNIX directory.
Read allows you to see and list the directory contents.
Write allows you to create, edit and delete files and subdirectories in the directory.
Execute gives you the previous read/write permissions plus allows you to change into the directory and execute programs or shells from the directory.
What is chmod, chown and chgrp?
Chmod : It is used for to change permissions on files
Chown : It is used for to change ownership of a file
Chgrp : It is used for to change group of the file
