Command to view what's written inside a file?
The "cat" command shows the content written inside the file.
cat <filename>
Example:
Suppose, we have one file named "file1.txt" and inside this file "Hello DevOps" is written. So, to view what is written inside the file you can type the following command in the terminal:
Command to change the access permission of a file?
The "chmod" command gives all permissions i.e. read, write and execute permissions to all ( Users, Groups and Others ).
chmod 777 file1.txt
In the above screenshot, file1.txt has all the permissions ( Read, Write, Execute )
Let's Understand how to provide permissions to a file in detail.
| Octal | File mode |
| 1 | --x, executable permission |
| 2 | --w, write permission |
| 3 | --r, read permission |
Suppose if we want to provide executable permission to groups, write permission to users and read permission to others, then the command should be like this
executable permission to groups i.e. octal "1"
write permission to users i.e. octal "2"
read permission to others i.e. octal "4"
command: chmod 124 file1.txt
Command to check which commands you have run till now.
"history" command shows us what all commands we have you till now.
history
Command to remove Directory/Folder in Linux?
To remove a directory or folder in Linux, you can use the "rmdir" or "rm" command.
To remove an empty directory
rmdir <directory-name>
To remove non-empty directories
rm -r <directory-name>
Here, -r means recursively.
Command to create a fruits.txt file and to view the content?
To create a file "touch" command is used
touch <filename>
To view the content of a file, the "cat" command is used
cat <filename>
Command to Add content in devops.txt (One in each line) - Apple, Mango, Banana, Cherry, Kiwi, Orange, Guava.
First create a file with "touch" command
Example: touch devops.txt
Open the devops.txt file with vim editor
vim, nano editors are used to add content to a file.
Example: vim devops.txt
Press "i" to go into insert mode and add contents to the file
and press "Esc + :wq" to save and exit from the file.
Command to show only top three fruits from the file?
The "head" command gives us the first part of a file.
head -n <filename>
"-n" option to specify the number of lines to display
Command to Show only bottom three fruits from the file.
The "tail" command gives us last part of a file.
tail -n <filename>
"-n" to specify the number of lines to display from the end of the file.
Command to create another file Colors.txt and to view the content.
To create the file "touch" command is used.
touch <filename>
To see the content of a file
cat <filename>
Command to add content in Colors.txt (One in each line) - Red, Pink, White, Black, Blue, Orange, Purple, Grey.
Open colors.txt file with vim editor
vim, nano editors are used to add content to a file.
Example: vim colors.txt
Press "i" to go into insert mode and add contents to the file
and press "Esc + :wq" to save and exit from the file.
Command to find the difference between fruits.txt and Colors.txt files.
**"diff" command is used to check the difference between two files.
diff <file1> <file2>
Let's understand the difference
Here in devops.txt we have content
Apple
red
blue
yellow
green
maroon
and in "colors.txt" file we have
red
blue
yellow
green
maroon
Each line will be prefixed with "<" or ">" to indicate which file it belongs to.
Happy Learning!!
Thanks For Reading! :)