Shell-Commands-part2

echo "Hello World" > devops.txt     //Output of echo "Hello World"  will be stored in devops.txt file .
man echo                          //man command is used to get information of a particular command . Here i am trying to know more about echo command.
cat devops.txt | tr a-z A-Z > DEVOPS.txt      //Here it says that for the content of devops.txt , translate each character to upper case and then store it in DEVOPS.txt
> Redirect symbol (Redirecting the output to another file)
| pipe symbol(output of first command will act as input for second command
touch devops.txt        //touch is used to create new file
cp devops.txt devops1.txt       //make copy of devops.txt as devops1.txt
mv devops.txt. devops1.txt      //rename/move devops.txt as devops1.txt 
cp -R  /test /test1             //copies the entire directory /test to /test1
rm  devops.txt              //delete a file 
rm -R   /test    //delete the directory test 
rm -rf /test     //If file/directory is opened then we can use -f option to forcefully delete it .
sudo            //Some commands need to be run as a superuser/admin user permission.It will ask for system password
df -h         //disk space and volume space (man df command) . -h is human readable format
ls -latr | head -n 10    //here Head command will show first 10 lines of ls command output
ls -latr | tail  -n 10    //here tail  command will show last  10 lines of ls command output
head and tail we can use in with file also . Like head -n 2 devops.txt
diff devops.txt devops1.txt     //To list difference between two files . It will show the content that is not there in both files
locate "*.txt"          //It will show all the files in the current work directory which wil have extension as .txt .
find . -type f -name "devops.txt"      //find command to find a file or dir in the current directory .here i have defined the type as file and finding the file devops.txt in current directory
* is wildcard . 

Note : For detail on any command use man and try different arguments with it .

Assignments :
1. Create a file demo.txt using touch command and write around 20 lines in this file.
2. Print the output of first 5 lines from demo.txt and then last 5 lines .
3. find all the files inside your home directory whose last modification date is minimumm 20 minutes .Note:use man command to see arguments
4. create a file server.txt in /home and then move server.txt with name as server1.txt to /home/random directory . Note you need to create random directory here.
5. Delete the file server1.txt and the directory /home/random