unix Basic console commands Basic Unix commands

Example

$pwd

Displays the present working directory.

$who

Displays all the users logged in.

$who am i

Shows the username of the current user.

$date

Displays the current system date

$which <command>

Shows the path of the specified command. For example "$which pwd" will shows the path of 'pwd' command.

$file <file_name>

Shows the type of the specified file(regular file, directory or other files)

$cal

Displays the calender of the current month.

$bc

Shows the mathematical calculation between two integers of floats. For example "$bc 2+3" will returns the arithmetic sum of 3 and 5.

$ls

Lists the contents of the directory.

• $ls -l : lists in long format.
• $ls -c : Multi column output.
• $ls -f : Lists the type of file.
• $ls -r : Recursive listing of all subdirectories encountered.
• $ls -a : Displays all files including hidden files.
• $ls -i : Lists all files along with its I-Node number.

$grep [options] <pattern> <input_file_names> 

Prints lines that contain a match for a pattern.

• $grep -i : Perform case insensitive matching
• $grep -v : Prints all lines that don’t contain the regex
• $grep -r : Recursively search subdirectories listed and prints file names with occurrence of the pattern
• $grep -I : Exclude binary files