How to use the command 'yank' (with examples)

The ‘yank’ command is a utility tool that allows the user to select specific fields from input data and copy them to the clipboard. It provides a selection interface that simplifies the task of extracting and copying data.

Use case 1: Yank using the default delimiters (\f, \n, \r, \s, \t)

Code:

sudo dmesg | yank

Motivation:

• As a system administrator, you may need to extract specific information from command outputs, such as kernel messages. The ‘yank’ command simplifies this task by allowing you to select and copy the desired field.

Explanation:

• The command ‘sudo dmesg’ displays kernel ring buffer messages.
• The pipe (|) symbol redirects the output of the ‘sudo dmesg’ command as input to the ‘yank’ command.
• The ‘yank’ command, by default, extracts fields from the input using delimiters such as spaces, tabs, newlines, etc.
• In this case, ‘yank’ reads the input from the ‘sudo dmesg’ command and displays a selection interface that allows you to choose a field.
• After selecting a field, the selected text is copied to the clipboard.

Example output:

• The output of ‘sudo dmesg’ will be displayed in a selection interface, where you can navigate and choose the desired field. Once selected, the field will be copied to the clipboard.

Use case 2: Yank an entire line

Code:

sudo dmesg | yank -l

Motivation:

• Sometimes, you may need to copy an entire line from input data rather than a specific field. The ‘yank’ command makes it easy to select and copy whole lines.

Explanation:

• The command ‘sudo dmesg’ displays kernel ring buffer messages.
• The pipe (|) symbol redirects the output of the ‘sudo dmesg’ command as input to the ‘yank’ command.
• The ‘-l’ flag is used to specify that the entire line should be copied instead of selecting specific fields.
• ‘yank’ reads the input from ‘sudo dmesg’ and displays a selection interface with each line as a choice.
• Upon selecting a line, the complete line is copied to the clipboard.

Example output:

• The output of ‘sudo dmesg’ will be displayed in a selection interface, where each line will be presented as a selectable choice. After selecting a line, the entire line will be copied to the clipboard.

Use case 3: Yank using a specific delimiter

Code:

echo hello=world | yank -d =

Motivation:

• There are scenarios where the default delimiters used by ‘yank’ may not be suitable for extracting the desired field. In such cases, you can specify a custom delimiter to extract the field using the ‘-d’ option.

Explanation:

• The command ’echo hello=world’ prints the string “hello=world”.
• The pipe (|) symbol redirects the output of the ’echo’ command as input to the ‘yank’ command.
• The ‘-d =’ flag is used to specify the delimiter as the equals sign (=).
• ‘yank’ reads the input from ’echo’ and extracts the field using the specified delimiter.
• The selected field is then copied to the clipboard.

Example output:

• The string “hello=world” will be displayed in a selection interface with “hello” and “world” as separate fields. Upon selecting either field, the chosen field will be copied to the clipboard.

Use case 4: Only yank fields matching a specific pattern

Code:

ps ux | yank -g "[0-9]+"

Motivation:

• In certain scenarios, you may only want to extract fields that match a specific pattern. The ‘yank’ command allows you to specify a pattern to filter and copy matching fields.

Explanation:

• The command ‘ps ux’ displays a snapshot of the current processes in a user-friendly format.
• The pipe (|) symbol redirects the output of the ‘ps ux’ command as input to the ‘yank’ command.
• The ‘-g “[0-9]+” option is used to specify a regular expression pattern to filter the fields.
• ‘yank’ reads the input from ‘ps ux’ and displays a selection interface with fields that match the specified regular expression.
• Only the fields matching the pattern will be available for selection and copying.

Example output:

• The output of ‘ps ux’ will be displayed in a selection interface, where only the fields containing numeric values will be presented as selectable choices. Once a field is selected, it will be copied to the clipboard.

Conclusion:

The ‘yank’ command provides a convenient way to extract specific fields or entire lines from input data and copy them to the clipboard. It offers flexibility in selecting delimiters and filtering fields based on regular expressions. By simplifying the process of extracting and copying data, ‘yank’ enhances productivity and streamlines administrative tasks.