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?
1 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.
