How to use the command `colrm` (with examples)

colrm is a command that can be used to remove columns from stdin. It allows you to extract specific columns from a file or remove unwanted columns.

Use case 1: Remove first column of stdin

Code:

colrm 1 1

Motivation: You may want to remove the first column of a file if it contains unnecessary or redundant information. This can be useful when cleaning up data or preparing it for further processing.

Explanation: The command colrm 1 1 will remove the first column of input from stdin. The first argument, 1, specifies the starting column number, and the second argument, also 1, specifies the ending column number.

Example output: Input:

1,apple,red
2,banana,yellow
3,orange,orange

Output:

apple,red
banana,yellow
orange,orange

Use case 2: Remove from the 3rd column till the end of each line

Code:

colrm 3

Motivation: In some cases, you may want to remove columns from a specific position till the end of each line. This can be useful when you want to discard certain data from the input.

Explanation: The command colrm 3 will remove columns starting from the third column till the end of each line. The first argument, 3, specifies the starting column, while the ending column is not provided, indicating it should go till the end of the line.

Example output: Input:

1,apple,red
2,banana,yellow
3,orange,orange

Output:

1
2
3

Use case 3: Remove from the 3rd column till the 5th column of each line

Code:

colrm 3 5

Motivation: There might be situations where you need to remove a range of columns from the input. Removing columns from a specific range can be helpful in cases where you want to filter or manipulate a specific subset of data.

Explanation: The command colrm 3 5 will remove columns from the third column till the fifth column of each line. The first argument, 3, specifies the starting column, and the second argument, 5, specifies the ending column.

Example output: Input:

1,apple,red,fruit,tree
2,banana,yellow,fruit,plant
3,orange,orange,fruit,tree

Output:

1,apple,tree
2,banana,plant
3,orange,tree

Conclusion:

The colrm command provides a convenient way to remove unwanted columns from stdin. Whether you need to remove the first column, discard columns from a specific position till the end, or remove columns within a range, colrm can help you manipulate and clean up data efficiently.