head: fix bug with non-terminated files. #7484
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sylvestre
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Mar 19, 2025
Fixes issue uutils#7472. Update to head app when printing all-but-last-n-lines of a file. Code now checks if the last line of the input file is missing a terminating newline character, and if so prints an extra line. This aligns with GNU-head behavior. Also improved performance of this usecase by using an optimized iterator (memchr-iter) for searching through the input file.
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Fixes #7472.
Update to head app when printing all-but-last-n-lines of a file.
Code now checks if the last line of the input file is missing a terminating newline character, and if so prints an extra line in the output. This aligns with GNU-head behavior.
Also made a change to improve performance of this usecase by using an optimized iterator (memchr-iter) for searching through the input file (gives a ~25% improvement for
head -n -100000 ./shakespeare.txtvs the current mainline tip).