Linux commands

Question 1

how to find a particular file in a directory ?
e.g find test.txt in /home/shrirang/ddd/xyd/

Answer 1

find ./data -name test.txt

Question 2

find all the files of an extension in a directory

Answer 2

find . -type f -name “*.txt”

Question 3

list all extension files in a directory

Answer 3

find . -type f | perl -ne ‘print $1 if m/.([^.\/]+)$/’ | sort -u

Question 4

basic grep command in single file

Answer 4

grep term filename

Question 5

grep in files with specific extensions

Answer 5

grep -inr –include *.h –include *.cpp {term} {path}

Question 6

list size of directories sorted

Answer 6

sudo du -hs * | sort -hr

Question 7

find a directory in a path and all its sub-directories

Answer 7

find . -type d -name “enom”
find . -type d -name “enom*”

Question 8

find a file in a path and all its sub-directories

Answer 8

find . -type file -name *.txt

Question 9

list the sizes of directories

Answer 9

sudo du -hs * | sort -hr

Question 10

How to print specified column in text

Answer 10

awk ‘{print $1}’

Question 11

Add user and make the user sudo and change password

Answer 11

useradd

sudo usermod -aG sudo

sudo passwd

Question 12

reset the /etc/apt/sources.list

Answer 12

sudo apt-get install –reinstall apt