Basic Syntax

The basic syntax for using a command-line tool consists of the command name followed by one or more arguments or options. An argument is a variable that provides a specific value to a command, while an option is a flag that modifies the behavior of a command. Usually, options are indicated by a hyphen (-) or double hyphen (--).

Here is an example of a basic command:

ls -l

This command lists the files and directories in the current directory in a long format.

Common Command-Line Tools

Here are some of the most frequently used command-line tools:

• cd: Changes the current directory.

• ls: Lists files and directories.

• cat: Concatenates files or displays them on the screen.

• mv: Moves or renames files and directories.

• cp: Copies files and directories.

• rm: Removes files and directories.

• mkdir: Creates a new directory.

• rmdir: Deletes a directory.

• grep: Searches for a pattern in a file or files.

• sed: Edits a file or stream.

• awk: Filters and processes text files.

Example Usage

Here are some examples of how these command-line tools can be used:

cd ~/Documents

Changes the current directory to the Documents folder in the user's home directory.

ls -la

Lists all files and directories in the current directory in a long format, including hidden files.

cat file.txt

Displays the contents of the file.txt file on the screen.

mv file.txt newfile.txt

Renames the file.txt file to newfile.txt.

cp file.txt ~/Documents/

Copies the file.txt file to the Documents folder in the user's home directory.

rm file.txt

Deletes the file.txt file.

mkdir newfolder

Creates a new folder named newfolder in the current directory.

rmdir newfolder

Deletes the newfolder directory if it is empty.

grep "example" file.txt

Finds all occurrences of the word "example" in the file.txt file.

sed 's/old/new/' file.txt

Replaces all occurrences of the word "old" with "new" in the file.txt file.

ls | awk '{print $1}'

Lists all files and directories in the current directory, displaying only the first column of output (the file/directory names).