* src/yes.c (splice_write): Always drain what we've written
to an internal pipe, so there is no possibility of vmsplice() blocking.
I.e., be defensive in the case that fcntl() fails, and
our default buffer size (currently 16kiB) is larger than the pipe.
https://github.com/coreutils/coreutils/issues/253
Bruno Haible [Fri, 17 Apr 2026 13:46:19 +0000 (15:46 +0200)]
tests: reinstate logname error verification
* tests/misc/user.sh: Modify the "unshare -U logname" test, so that it
does not fail on glibc versions (< 2.28, >= 2.38) that do a fallback
lookup based on the tty.
* tests/date/date-locale-hour.sh: Just strip the char before the last x,
assuming it's going to be the newline output by `locale`.
dash doesn't support $'' within ${}.
* tests/misc/io-errors.sh: Allow a generic error string on musl since
the first line is emitted immediately instead of being buffered as
expected.
Reported by Bruno Haible.
* m4/jm-macros.m4: AIX has a splice() function for TCP,
so check for vmsplice() instead.
* src/splice.h: Define HAVE_SPLICE if vmsplice available.
Reported by Bruno Haible.
* tests/dd/no-allocate.sh: Run getlimits_ to ensure
we have $SSIZE_MAX etc. available. Also give some buffer
for the configured ulimit to leave space for returns_ to work.
* tests/cp/sparse-perf.sh: Old Centos 7 can give EINVAL
from SEEK_DATA on sparse files being copied from /dev/shm.
Avoid this failure as it's not practical to fix.
* tests/date/date-locale-hour.sh: Ensure `locale date_fmt`
is propagated exactly, even when it contains trailing new lines,
as was seen with Serbian locales on Centos 7.
As noted in https://bugs.gnu.org/9089
ksh gives intermittent ECONNRESET errors with closed pipes.
This can be seen reliably on Linux with:
ksh -c 'yes | (sleep .1; head -n10 >/dev/null)'
* tests/misc/io-errors.sh: Avoid part of test on ksh.
* tests/misc/write-errors.sh: Likewise.
As described in commit v9.10-283-g5cb0cca3b
avoid using ulimit with $SHELL -c, and explict
invocation of the shell like that can require lots of memory,
often due to loading the locale archive.
* tests/basenc/bounded-memory.sh: Avoid $SHELL -c with ulimit.
* tests/cut/bounded-memory.sh: Likewise.
* tests/expand/bounded-memory.sh Likewise.
* tests/pr/bounded-memory.sh Likewise.
* tests/unexpand/bounded-memory.sh Likewise.
* tests/fold/fold-zero-width.sh: Bring the ulimit bound
down to the standard 6M over the determined limit.
* tests/misc/tty-eof.pl: Fix a race that commit v9.10-269-gf312af49a
made more apparent, and resulted in intermittent failure like:
"... (with input) didn't produce expected output".
Now Instead of waiting for overlapping echo and output,
just wait for EOF, and if received, use exp->before()
to inspect the accumulated output.
Verified with:
make -j4 PREFERABLY_POSIX_SHELL=/bin/ksh SUBDIRS=. check
* tests/fold/fold-zero-width.sh: Don't timeout $SHELL -c ...
as the ulimit induces a failure in the subshell depending
on the order of the allocations it does. The main issue is
disparity between the probed ulimit and that needed by $SHELL -c.
Such subshells load the often very large locale archive, thus
if there are any allocations done after the now too low ulimit is set,
then the $SHELL command fails. Note we timeout fold rather than
the whole pipeline so any 124 exit status is propagated.
$ strace -e silence=exit -e trace=unlink,rmdir \
mktemp -d > /dev/full
unlink("/tmp/tmp.ZBuPmS9ZGD") = -1 EISDIR (Is a directory)
rmdir("/tmp/tmp.ZBuPmS9ZGD") = 0
mktemp: write error: No space left on device
In the above invocation we know that we created a directory, so we
should not remove a regular file that must have been created by another
process:
$ strace -e silence=exit -e trace=unlink,rmdir \
./src/mktemp -d > /dev/full
rmdir("/tmp/tmp.hGbME1HmJr") = 0
mktemp: write error: No space left on device
* src/mktemp.c (main): Prefer rmdir and unlink depending on whether we
created a directory or regular file.
* bootstrap.conf (gnulib_modules): Remove the remove module.
* src/cat.c (splice_cat): Don't bother resizing input as it generally
doesn't help perf, and also save an fstat per input. Don't close the
intermediate pipe once created, unless there is an error reading from
it.
* tests/misc/responsive.sh: Test commands that should output immediately
upon receiving input, and that there is no unecessary buffering.
* cfg.mk: Avoid false failure in sc_prohibit_test_backticks.
* tests/local.mk: Reference the new test.
* tests/tty/tty-eof.pl: Remove command specific logic,
and adjust commands to support general input.
Also add cut -b, as cut_bytes has its own read loop.
* tests/date/date.pl: Set the max supported year to INT_MAX.
Most systems support INT_MAX+1900, but mktime() on OpenBSD 7.8
limits the passed tm_year to INT_MAX.
Reported by Bruno Haible.
tests: numfmt: avoid false failure on systems without long double
* tests/numfmt/numfmt.pl: Move recently added test that depends
on long double support to the appropriately guarded set.
Also reduce the value to be in the definitely safe long double range.
Reported by Bruno Haible.
Seen on GCC 15.2.1 with GLIBC 2.43 on Arch
Not seen on GCC 15.2.1 on GLIBC 2.42 on Fedora
* src/cut.c (search_bytes): Cast the return from memchr()
to avoid const propagation.
(find_field_delim): Adjust the return from strstr() similarly.
https://github.com/coreutils/coreutils/issues/244
tests: cat: avoid false failure on systems without splice
* tests/cat/splice.sh: Ensure splice is called multiple times
before we check specific invocation counts.
On Linux kernel 5.10 for example, splice from /dev/zero
returns EINVAL.
* NEWS: Mention the improvement.
* src/cat.c: Include isapipe.h, splice.h, and unistd--.h.
(splice_cat): New function.
(main): Use it.
* src/local.mk (noinst_HEADERS): Add src/splice.h.
* src/splice.h: New file, based on definitions from src/yes.c.
* src/yes.c: Include splice.h.
(pipe_splice_size): Use increase_pipe_size from src/splice.h.
(SPLICE_PIPE_SIZE): Remove definition, moved to src/splice.h.
* tests/cat/splice.sh: New file, based on some tests in
tests/misc/yes.sh.
* tests/local.mk (all_tests): Add the new test.
* tests/date/date.pl: Add the test case.
Add test case for https://github.com/uutils/coreutils/issues/9774
to verify with large dates.
https://github.com/coreutils/coreutils/pull/237
Paul Eggert [Mon, 6 Apr 2026 18:12:46 +0000 (11:12 -0700)]
maint: revert “avoid pthread_sigmask lock”
* configure.ac (GNULIB_SIGACTION_SINGLE_THREAD): Remove.
This never worked (it was a misspelling) and the properly-spelled
identifier (whose spelling has since been renamed) is useful
mostly for programs like gzip that do not need Gnulib’s ‘lock’ module.
For coreutils, which needs ‘lock’ for other reasons, it’s overkill.
maint: avoid pthread_sigmask lock overhead
This matters only for MS-Windows.
* configure.ac (GNULIB_PTHREAD_SIGMASK_SINGLE_THREAD):
Define this instead of defining GNULIB_SIGACTION_SINGLE_THREAD.
The latter was a typo, and Gnulib has evolved anyway.
tests: expr: add short-circuit tests with parenthesized branches
* tests/expr/expr.pl: Add tests to verify that short-circuit
evaluation of | and & correctly skips parenthesized dead branches,
including nested parenthesized expressions containing division by zero.
https://github.com/uutils/coreutils/pull/11395
https://github.com/coreutils/coreutils/pull/238
tests: split: verify non-UTF-8 bytes are preserved in filenames
* tests/split/non-utf8.sh: New test to ensure that non-UTF-8 bytes
in the prefix and --additional-suffix are preserved as-is in output
filenames, rather than being replaced by UTF-8 replacement characters.
* tests/local.mk: Register new test.
https://github.com/uutils/coreutils/pull/11397
https://github.com/coreutils/coreutils/pull/239
tests: ln: add test for non-UTF-8 source names in target-dir mode
* tests/ln/non-utf8-src.sh: New test ensuring ln handles source
filenames containing non-UTF-8 bytes when linking into a target
directory, for both hard links and symbolic links with -t.
* tests/local.mk: Register the new test.
https://github.com/uutils/coreutils/pull/11403
https://github.com/coreutils/coreutils/pull/240
test: od: verify -t f defaults to double precision
* tests/od/od-float.sh: Add cases to ensure -t f = -t fD,
and also verify the resulting number.
https://github.com/uutils/coreutils/pull/11396
https://github.com/coreutils/coreutils/pull/241
tests: ls: add quoting-utf8 test for Unicode quotes in UTF-8 locales
* tests/ls/quoting-utf8.sh: New test verifying that
--quoting-style=locale and --quoting-style=clocale use Unicode
left/right single quotation marks in UTF-8 locales, and that
embedded apostrophes and double quotes are not escaped when the
delimiters are different characters.
Also check C locale fallback to ASCII quotes.
* tests/local.mk: Reference the new test.
https://github.com/coreutils/coreutils/pull/243
Pádraig Brady [Thu, 12 Mar 2026 17:49:27 +0000 (17:49 +0000)]
doc: document cut(1) multi-byte and interface consolidation
This patch set updates cut(1) to be multi-byte aware.
It also reduces interface divergence across implementations.
multi-byte awareness was added to the existing -c, n, and -d options.
Also considered for compatibility are the -w, -F, and -O options,
as these are present on at least two other common implementations.
= Interface / New functionality =
macOS, i18n, uutils, Toybox, Busybox, GNU
-c x x x x x x
-n x x x
-w x x x
-F x x x
-O x x x
-c is needed anyway as specified by all, including POSIX.
-n is needed also as specified by i18n/macOS/POSIX
-w is somewhat less important, but seeing as it's
on two other common platforms (and its functionality is
provided on two more), providing it is worthwhile for compat.
-F and -O are really just aliases to other options
so trivial to add, and probably worthwhile for compatibility.
Interface / functionality notes:
There is a slight divergence between -n implementations.
There was already a difference between FreeBSD and i18n, and
we've aligned with the more sensible FreeBSD implementation.
Note the i18n -n implementation is otherwise buggy in any case,
so I doubt this will be a practical compatibility concern.
Actually -n is specified by POSIX, and it matches FreeBSD.
Specifically our -n will not output a character unless the
byte range encompasses _the end_ of the multi-byte character.
I.e. the -b is a limit that is not passed, and thus ensures
we don't output overlapping characters for separate cut
invocations that do not have overlapping byte ranges.
-d <regex> from toybox is not implemented.
That's edge case functionality IMHO and not well suited to cut(1).
This functionality is supported by awk, and regex functionality
is best restricted to awk I think.
cut is a significant part of the i18n patch, so it will be good
to avoid that downstream divergence. Unfortunately there were
no tests with the cut i18n implementation.
Note the i18n cut implementation used fread() as so was
not reponsive to new data < BUFSIZ, whereas this implementation
uses read() and thus is responsive to data as it becomes available.
= Performance =
General performance notes:
We prefer byte searching (with -d) as that can be much faster
than character by character processing, and it's supported
on single byte and UTF-8 charsets. We also use byte searching
with -w on uni-byte locales.
This was seen to give up to 100x perf increase over the i18n patch.
Where we do use per character processing, we avoid conversion to
wide char when processing ASCII data (mcel provides this optimization).
This was seen to give a 14x performance increase over the i18n patch.
We prefer memchr() and strstr() as these are tuned for specific
platforms on glibc, even if memchr2() or memmem()
are algorithmically better.
We maintain the important memory behavior
of only buffering when necessary.
Performance testing:
There are _lots_ of combinations and optimziation opportunities.
I performance tested this patch set with the following setup:
$ yes | head -n10M > sl.in
$ yes $(yes eeeaae | head -n10K | paste -s -d,) | head -n10K > ll.in
$ yes $(yes eeeaae | head -n9 | paste -s -d,) | head -n1M > as.in
$ yes $(yes éééááé | head -n9 | paste -s -d，) | head -n1M \
> mb.in
$ for type in sl ll as mb; do
cat $type.in >/dev/null;
for imp in '' src/; do # '' maps to the system i18n ver on Fedora
echo ============ "${imp:-i18n}" $type ==============;
for d in -d, -dc -d， -dç -w -b -c; do
fields='-f1 -f10 -f100'
test "$d" = "-b" && { fields='-b1 -b10 -b100'; d=''; }
test "$d" = "-c" && { fields='-c1 -c10 -c100'; d=''; }
for f in $fields; do
for loc in C C.UTF-8; do
# SKip -b for UTF-8 as no different
test "$loc" = C.UTF-8 && echo "$f" | grep -q -- -b \
&& continue
# Skip multi-byte delimiter for C and not allowed
test "$loc" = C && test $(echo -n "$d" | wc -c) -ge 4 \
&& continue
LC_ALL=$loc ${imp}cut $f $d /dev/null 2>/dev/null &&
hyperfine -m2 -M4 \
"LC_ALL=$loc ${imp}cut $f $d $type.in >/dev/null" ||
printf 'Benchmark 1: %s\n unsupported\n\n' \
"LC_ALL=$loc ${imp}cut $f $d $type.in >/dev/null"
done;
done;
done;
done;
done
After a little post-processing of the results, we get:
-- cut-i18n
| command | sl | ll | as | mb |
| --------------- | -------- | -------- | -------- | -------- |
| C -f1 -d, | 66.3 ms | 1.605 s | 145.9 ms | 366.4 ms |
| UTF8 -f1 -d, | 65.8 ms | 1.593 s | 145.8 ms | 370.0 ms |
| C -f10 -d, | 301.4 ms | 1.590 s | 161.8 ms | 126.7 ms |
| UTF8 -f10 -d, | 303.5 ms | 1.599 s | 161.8 ms | 124.6 ms |
| C -f100 -d, | 300.6 ms | 1.596 s | 162.1 ms | 126.7 ms |
| UTF8 -f100 -d, | 301.3 ms | 1.595 s | 162.0 ms | 124.9 ms |
| C -f1 -dc | 66.6 ms | 1.845 s | 179.1 ms | 365.7 ms |
| UTF8 -f1 -dc | 73.8 ms | 1.878 s | 179.1 ms | 363.1 ms |
| C -f10 -dc | 300.7 ms | 349.8 ms | 76.0 ms | 125.3 ms |
| UTF8 -f10 -dc | 300.4 ms | 347.2 ms | 75.7 ms | 124.8 ms |
| C -f100 -dc | 300.1 ms | 348.1 ms | 76.5 ms | 125.5 ms |
| UTF8 -f100 -dc | 300.8 ms | 348.7 ms | 76.4 ms | 125.8 ms |
| UTF8 -f1 -d， | 563.5 ms | 21.775 s | 1.963 s | 1.665 s |
| UTF8 -f10 -d， | 833.6 ms | 20.504 s | 2.022 s | 1.612 s |
| UTF8 -f100 -d， | 825.2 ms | 20.448 s | 2.009 s | 1.616 s |
| UTF8 -f1 -dç | 563.7 ms | 21.827 s | 1.964 s | 2.319 s |
| UTF8 -f10 -dç | 825.3 ms | 21.713 s | 2.011 s | 2.248 s |
| UTF8 -f100 -dç | 831.6 ms | 20.505 s | 2.019 s | 2.276 s |
| C -f1 -w | - | - | - | - |
| UTF8 -f1 -w | - | - | - | - |
| C -f10 -w | - | - | - | - |
| UTF8 -f10 -w | - | - | - | - |
| C -f100 -w | - | - | - | - |
| UTF8 -f100 -w | - | - | - | - |
| C -b1 | 60.8 ms | 1.596 s | 154.8 ms | 313.7 ms |
| C -b10 | 51.6 ms | 1.594 s | 154.3 ms | 310.8 ms |
| C -b100 | 51.4 ms | 1.594 s | 153.0 ms | 312.2 ms |
| C -c1 | 60.7 ms | 1.597 s | 153.8 ms | 313.0 ms |
| UTF8 -c1 | 526.5 ms | 14.662 s | 1.362 s | 1.573 s |
| C -c10 | 51.8 ms | 1.591 s | 153.3 ms | 311.4 ms |
| UTF8 -c10 | 436.9 ms | 14.450 s | 1.336 s | 1.563 s |
| C -c100 | 51.0 ms | 1.593 s | 152.7 ms | 313.2 ms |
| UTF8 -c100 | 426.7 ms | 14.429 s | 1.344 s | 1.551 s |
-- src/cut
| command | sl | ll | as | mb |
| --------------- | -------- | -------- | -------- | -------- |
| C -f1 -d, | 4.6 ms | 108.2 ms | 45.4 ms | 24.2 ms |
| UTF8 -f1 -d, | 4.8 ms | 108.4 ms | 45.4 ms | 24.5 ms |
| C -f10 -d, | 4.5 ms | 109.3 ms | 123.7 ms | 24.3 ms |
| UTF8 -f10 -d, | 4.9 ms | 114.1 ms | 124.1 ms | 24.5 ms |
| C -f100 -d, | 4.7 ms | 119.2 ms | 124.1 ms | 24.5 ms |
| UTF8 -f100 -d, | 4.8 ms | 120.0 ms | 125.1 ms | 24.5 ms |
| C -f1 -dc | 4.4 ms | 120.5 ms | 11.9 ms | 24.1 ms |
| UTF8 -f1 -dc | 4.9 ms | 120.5 ms | 12.1 ms | 24.6 ms |
| C -f10 -dc | 4.7 ms | 125.3 ms | 11.8 ms | 24.1 ms |
| UTF8 -f10 -dc | 4.8 ms | 126.7 ms | 12.0 ms | 24.4 ms |
| C -f100 -dc | 4.6 ms | 127.0 ms | 11.9 ms | 24.3 ms |
| UTF8 -f100 -dc | 4.7 ms | 126.4 ms | 12.0 ms | 24.4 ms |
| UTF8 -f1 -d， | 6.0 ms | 169.4 ms | 15.6 ms | 67.4 ms |
| UTF8 -f10 -d， | 6.1 ms | 173.9 ms | 15.6 ms | 237.2 ms |
| UTF8 -f100 -d， | 6.1 ms | 174.0 ms | 15.6 ms | 237.8 ms |
| UTF8 -f1 -dç | 6.3 ms | 170.8 ms | 15.7 ms | 32.2 ms |
| UTF8 -f10 -dç | 6.0 ms | 172.9 ms | 15.9 ms | 32.1 ms |
| UTF8 -f100 -dç | 6.7 ms | 173.1 ms | 15.5 ms | 32.3 ms |
| C -f1 -w | 159.6 ms | 170.1 ms | 69.1 ms | 98.9 ms |
| UTF8 -f1 -w | 128.1 ms | 2.525 s | 246.5 ms | 1.086 s |
| C -f10 -w | 183.3 ms | 199.2 ms | 74.6 ms | 105.0 ms |
| UTF8 -f10 -w | 130.3 ms | 2.659 s | 276.5 ms | 1.099 s |
| C -f100 -w | 183.8 ms | 202.5 ms | 74.1 ms | 103.6 ms |
| UTF8 -f100 -w | 130.1 ms | 2.663 s | 276.6 ms | 1.097 s |
| C -b1 | 65.0 ms | 110.2 ms | 22.4 ms | 35.6 ms |
| C -b10 | 48.7 ms | 109.6 ms | 24.2 ms | 36.7 ms |
| C -b100 | 48.7 ms | 110.6 ms | 19.0 ms | 36.6 ms |
| C -c1 | 65.8 ms | 109.5 ms | 22.4 ms | 35.6 ms |
| UTF8 -c1 | 63.2 ms | 1.130 s | 116.9 ms | 610.2 ms |
| C -c10 | 48.7 ms | 109.8 ms | 24.3 ms | 36.8 ms |
| UTF8 -c10 | 39.7 ms | 1.133 s | 118.7 ms | 610.0 ms |
| C -c100 | 48.3 ms | 110.7 ms | 18.9 ms | 36.7 ms |
| UTF8 -c100 | 39.4 ms | 1.141 s | 115.0 ms | 598.8 ms |
In summary, compared to the i18n patch we're now as fast in all cases,
and much faster in most cases.
We can see the -f byte searching performing well,
being 120x faster in the no matching delimiter case,
to at least 3x faster in the matching delimiter case.
When we resort to per character processing we also compare well,
being 14x faster in the ASCII processing case
(due to mcel short-circuiting the wide char conversion).
Note the processing mb.in results above also show a 2x win
in per character processing cases, but the i18n patch would have
also picked that win up as it's achieved separately to this patch set:
https://lists.gnu.org/r/coreutils/2026-03/msg00117.html
cut,fold,expand,unexpand: ensure we process all available characters
* gl/lib/mbbuf.h: Adjust mbbuf_fill() to process full characters
in the slop at the end of a read(). Previously valid characters
in the last MCEL_LEN_MAX bytes were ignored until the next read().
* src/cut.c (cut_fields_bytesearch): Adjust to the new naming.
* NEWS: Mention the fold(1) responsiveness fix, which was
improved with the change from fread() to read(),
and completed with this patch.
$ time LC_ALL=C src/cut-before -b1 sl.in >/dev/null
real 0m0.115s
$ time LC_ALL=C src/cut-after -b1 sl.in >/dev/null
real 0m0.076s
* src/cut.c (cut_bytes): Hoist the fileno() invariant outside the loop.
Avoid memchr for very short lines.
(search_bytes): Similar to copy_bytes() and write_bytes() helpers.
Note adding code to probe 3 or 4 bytes resulted in worse register
allocation. I.e. slower operation even if the input was only 2 bytes.
cut: fix logic issue with field delim in last byte of buffer
With field delimiter = line delimiter we need to know
if there is any more data to be read, as field delimiter
in the last byte of the file is treated differently.
So reiterate the loop to ensure enough read()s to make
the appropriate determination.
* gl/lib/mbbuf.h (fill_buf): Switch from fread() to read()
as the former retries read() internally to fill the buffer.
* src/cut.c: Adjust accordingly, and avoid getc() interface entirely.
* bootstrap.h: Depend explicitly on fseterr. This is already depended
on transitively, so should not introduce new build portability issues.
Pádraig Brady [Sat, 28 Mar 2026 16:18:41 +0000 (16:18 +0000)]
doc: cut: clarify that combining characters are not treated specially
This is for consistency with other implementations and since the
interface separates -b and -c it might in future support -g (graphemes).
Normalizing content with a filter seems like the most appropriate
approach anyway, as there are various normalizations possible including
case etc. rather than baking that into every tool
Pádraig Brady [Sat, 28 Mar 2026 09:12:39 +0000 (09:12 +0000)]
doc: cut: resintate and expand -d info
* doc/coreutils.texi (cut invocation): Add back the -d description,
and adjust for multi-byte support, and expand on specifying a NUL
delimitier, and detail the behavior when the delimiter matches
the line delimiter.
Pádraig Brady [Fri, 27 Mar 2026 18:59:01 +0000 (18:59 +0000)]
cut: optimize UTF-8 input with 0xF5-0xFF delimiters
* src/cut.c (bytesearch_field_delim_ok): Expand the range
of bytes that can be simply searched for. 0xF5-0xFF can't
appear in valid UTF-8 characters, and so may be used as
delimiters in UTF-8 input, so it's worth optimizing for.
* tests/cut/cut.pl: Add a test case (mainly as documentation).
Pádraig Brady [Fri, 27 Mar 2026 18:29:16 +0000 (18:29 +0000)]
doc: cut: clarify that -s suppressed lines with only trimmed spaces
* doc/coreutils.texi (cut invocation): State explicitly that
-s --whitespace-delimited=trimmed will suppress lines that
do not have field separating blanks.
Pádraig Brady [Thu, 26 Mar 2026 16:52:56 +0000 (16:52 +0000)]
maint: cut: simplify mbbuf_fill
We can only byte search with uni-byte or utf-8.
utf-8 implicitly can't false match a delimiter at buffer boundary.
So don't worry about finding the exact utf8 boundary at end of buffer,
rather just ensuring the buffer always starts with a valid character
(by ensuring MCEL_LEN_MAX-1 moved to start of buffer on each refill).
Pádraig Brady [Tue, 24 Mar 2026 18:53:03 +0000 (18:53 +0000)]
cut: enable fast path for all delimiter lengths
1. Removed !have_pending_line from the fast path condition.
This is safe because:
- field_1_n_bytes == 0 already ensures we haven't started
buffering field 1 content
- The fast path correctly continues any pending partial line
by writing raw bytes including the completing \n
2. Added have_pending_line = false after the fast path write,
since all lines up to the last \n are now complete.
$ time src/cut.before -f1 -dç sl.in >/dev/null
real 0m0.081s
$ time src/cut.after -f1 -dç sl.in >/dev/null
real 0m0.012s
$ time src/cut.before -f10 -dç sl.in >/dev/null
real 0m0.081s
$ time src/cut.after -f10 -dç sl.in >/dev/null
real 0m0.012s
Pádraig Brady [Tue, 24 Mar 2026 15:35:24 +0000 (15:35 +0000)]
cut: optimize -b for short lines
For a 40% performance increase it's worth reinstating the simple
original cut_bytes() which avoids data copying and function calls.
Once a longer line is encountered we defer to the buffered variant.
$ time src/cut.before -b2 sl.in >/dev/null
real 0m0.101s
$ time src/cut.after -b2 sl.in >/dev/null
real 0m0.060s
Pádraig Brady [Sun, 22 Mar 2026 12:20:04 +0000 (12:20 +0000)]
cut: optimize -b by avoiding per byte iteration
Always memchr(line_delim) which is fast and allows:
- skipping whole segments when the next selected byte is beyond them
- skipping unselected prefixes in bulk
- writing contiguous selected spans in bulk
This wins for lines >= 4 characters,
but is slower lines <= 3 characters, especially if selecting bytes 1-3.
That is unusual though.
Pádraig Brady [Sat, 21 Mar 2026 14:15:48 +0000 (14:15 +0000)]
cut: optimize when no delimiter in input
This is about 20x faster.
Note we only do the delimiter search once per chunk,
and it's usually quick as delimiters wouldn't be too far
into the a chunk if present, so we don't bother
to cache the found delimiter.
Pádraig Brady [Fri, 20 Mar 2026 17:07:18 +0000 (17:07 +0000)]
doc: cut: document the -w option
* src/cut.c (usage): Mention blank characters are used to separate.
* doc/coreutils.texi (cut invocation): Likewise. Also describe
the 'trimmed' argument and the relation to -F.
projects / thirdparty / coreutils.git / log
