Skip to content

12.Working_With_Files.md

Latest commit

 

History

History
97 lines (66 loc) · 2.4 KB

12.Working_With_Files.md

File metadata and controls

97 lines (66 loc) · 2.4 KB

Working with Files

1. Creation of Files

In Linux, we can create files in the following ways:

  1. By using the touch command (to create an empty file)
  2. By using the cat command
  3. By using editors like gedit, vi, nano, etc.

cat Command

cat > file1.txt

Example:

$ cat > file1.txt
Hello Friends
Listen Carefully
Otherwise Linux will give
Left and Right
  • Press ctrl+d to save and exit.

If file1.txt is not already available, it will be created with the provided data. If file1.txt already exists with some content, the old data will be overwritten with the new data.

To append instead of overwriting, use >> with the cat command.

cat >> file1.txt

Example:

$ cat >> file1.txt
extra content
  • Press ctrl+d to save and exit.

Q&A

  • Q1. What is the difference between touch and cat?

    touch is used for creating an empty file, whereas cat is used for creating a file with some content.

  • Q2. How can we perform overwriting and appending with the cat command?

    > is meant for overwriting and >> is meant for appending/concatenation.

  • Q3. If we use the touch command, but the file is already available, what will happen?

    The content of the file won't change, but the last modified date and time (timestamp) will be updated.

Case Study

Assume that we have a shell script that sends all current date files to a remote server. This script doesn't run on Saturdays and Sundays. However, on Monday, it needs to send files from all three days. The script only recognizes current date files, so to change the timestamp of Saturday and Sunday files, we can use the touch command.

Note: The touch command can be used for two main purposes:

  • To create an empty file
  • To change the timestamp of an existing file

2. Viewing of Files

We can view the contents of a file using the following commands:

  1. cat
  2. tac
  3. rev
  4. head
  5. tail
  6. less
  7. more

Text Editors Comparison

  • gedit: Similar to Windows Notepad
  • vi editor
    • Open file: vi file3.txt
    • The editor opens in command mode
    • Enter insert mode: Press i
    • Add your required data
    • Return to command mode: Press ESC
    • Save and exit: Type :wq
  • vim editor: Advanced version of vi editor
  • nano editor: nano file4.txt
    • Save: ctrl+O
    • Exit: ctrl+X