Practical 4

4.  List and Explain basic Linux commands.


Basic Linux commands are

  • ls
  • mkdir
  • cd
  • pwd
  • cat
  • more
  • head and tail
  • rm
  • cp
  • chmod
  • grep
  • date
  • cal
  • whoami


ls Command
ls : This is a list command. It will display the list of directory without any details.
ls – al : This will display the formatted  list of files and directories along with hidden files and other details like time, date, size, permissions etc.
ls – t : it will display the sorted formatted list of files and directories other details like time, date, size, permissions etc..

mkdir command
This command is used to create the directory.
Example: student@abg2:$ mkdir Patel
It will create the directory Patel

cd command
cd:  This command will change from current directory to home directory or from current to specified directory.
Example: student@abg2:~$ cd Patel                This will change to Patel directory
student@abg2:~/Patel$ cd                                This will change to home directory.
student@abg2:~$

pwd Command
This command will show the present or current working directory.
Example: student@abg2:~/Patel$ pwd
/home/student/Patel      this the path of present working directory.

cat command
cat command is used to create a new file, to add the new content in an existing file at the end of the file and view the content of existing file.

cat > sample.txt          This will create a new file sample.txt but if the file with same name already      exist then it overwrites.
cat < sample.txt          This is used to view the content of the file.

cat >> sample.txt        This allow you to add the new content at the end of the file.

more command
This command is used to output the content of the file.
more sample.txt 

head and tail command
head sample.txt            The head command will display the first 10 lines of the file sample.txt
tail sample.txt              The tail command will display the last 10 lines of the file sample.txt

rm command
rm sample.txt               This will remove the file sample.txt
rm – r Patel                  This will remove the directory Patel


cp Command               This is a copy command
cp file1 file2                            This command will copy the content of file1 to file2
cp sample.txt newsample.txt    Here it will copy the content of sample.txt to newsample.txt
cp – r dir1 dir2                         This command will copy the files of dir1 to dir2. If dir2 does not exist                                                   then it create the dir2 and copy the files.

chmod command         Change the permission on file for  user.

• 4-read(r)
• 2-write(w)
• 1-execute(x)
Example: chmod 444 sample.txt                    This will set the permission on the file that is 444, means
                                                                        for all user have the permission see/read the file but                                                                                can’t go for any write or execute operations.

chmod 777 sample.txt                         All user will be having all the permission that is read, write 
                                                            and execute.

grep command           
This command is used for searching the specific pattern in the file, within the files in the directory.

grep pattern file           Here it will Search for pattern in file and display all the line in which the
                                     pattern is found.
Example: grep Patel sample.txt          This will search for the pattern in the sample.txt and will output all the lines in which the pattern is found and search pattern is highlighted.
grep -r pattern dir         It will recursively search for the pattern in the directory and output the line
                                     from the different file where the pattern is found.

Example: grep –r Patel student       This will search for the pattern Patel in the student directory.

System Info Command
date command will Show the current date and time
cal command will Show current  month's calendar
             whoami command will display the current user name in which you are logged in

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