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fangio
Asked: 2019-10-06 02:29:47 +0800 CST

Difference between head and tail

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Why is there a difference between the meaning of NUM in head -c and tail -c?

I will clarify what I mean with the following commands:

$ echo "words" | tail -c +1
words
$ echo "words" | tail -c +2
ords
$ echo "words" | head -c -1
words$ echo "words" | head -c -2
word$

The first command does nothing.
The second command removes the first letter.
The third command removes the newline.
The last command removes the last 2 characters including the newline.

So why does head removes 2 bytes when using -c and tail only one. This looks like some real inconsistency or is there an underlying meaning?

command-line tail

1 Answers

  1. Best Answer

    Citing man tail:

    use -c +NUM to output starting with byte NUM of each file

    Citing man head:

    -c (…) [-]NUM
    with the leading '-', print all but the last NUM bytes of each file(…)

    The logic with

    tail -c +1

    is to print all from byte number 1, i.e. the first byte, while with

    head -c -1

    it’s to print all but the last 1 byte.

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