4fca8e0f65
This update contains only documentation changes (new main repository URL and changed mail address of the program author) and changes to the build system that do not affect the FreeBSD base system build. MFC after: 3 days
214 lines
7.0 KiB
Plaintext
214 lines
7.0 KiB
Plaintext
/*
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* *****************************************************************************
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2018-2023 Gavin D. Howard and contributors.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* *****************************************************************************
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*
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* The dc help text.
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*
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*/
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usage: %s [options] [file...]
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dc is a reverse-polish notation command-line calculator which supports unlimited
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precision arithmetic. For details, use `man %s` or see the online documentation
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at https://git.gavinhoward.com/gavin/bc/src/tag/%s/manuals/bc/%s.1.md.
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This dc is (mostly) compatible with the OpenBSD dc and the GNU dc. See the
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OpenBSD man page (http://man.openbsd.org/OpenBSD-current/man1/dc.1) and the GNU
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dc manual (https://www.gnu.org/software/bc/manual/dc-1.05/html_mono/dc.html)
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for details.
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This dc has a few differences from the two above:
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1) When printing a byte stream (command "P"), this bc follows what the FreeBSD
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dc does.
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2) This dc implements the GNU extensions for divmod ("~") and modular
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exponentiation ("|").
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3) This dc implements all FreeBSD extensions, except for "J" and "M".
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4) This dc does not implement the run command ("!"), for security reasons.
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5) Like the FreeBSD dc, this dc supports extended registers. However, they are
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implemented differently. When it encounters whitespace where a register
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should be, it skips the whitespace. If the character following is not
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a lowercase letter, an error is issued. Otherwise, the register name is
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parsed by the following regex:
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[a-z][a-z0-9_]*
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This generally means that register names will be surrounded by whitespace.
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Examples:
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l idx s temp L index S temp2 < do_thing
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Also note that, unlike the FreeBSD dc, extended registers are not even
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parsed unless the "-x" option is given. Instead, the space after a command
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that requires a register name is taken as the register name.
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Options:
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-C --no-digit-clamp
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Disables clamping of digits that are larger than or equal to the current
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ibase when parsing numbers.
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This means that the value added to a number from a digit is always that
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digit's value multiplied by the value of ibase raised to the power of the
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digit's position, which starts from 0 at the least significant digit.
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If multiple of this option and the -c option are given, the last is used.
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-c --digit-clamp
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Enables clamping of digits that are larger than or equal to the current
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ibase when parsing numbers.
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This means that digits that the value added to a number from a digit that
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is greater than or equal to the ibase is the value of ibase minus 1 all
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multiplied by the value of ibase raised to the power of the digit's
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position, which starts from 0 at the least significant digit.
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If multiple of this option and the -C option are given, the last is used.
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{{ A H N HN }}
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-E seed --seed=seed
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Sets the builtin variable seed to the given value assuming that the given
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value is in base 10. It is a fatal error if the given value is not a valid
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number.
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{{ end }}
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-e expr --expression=expr
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Run "expr" and quit. If multiple expressions or files (see below) are
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given, they are all run. After running, dc will exit.
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-f file --file=file
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Run the dc code in "file" and exit. See above.
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-h --help
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Print this usage message and exit.
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-I ibase --ibase=ibase
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Sets the builtin variable ibase to the given value assuming that the given
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value is in base 10. It is a fatal error if the given value is not a valid
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number.
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-i --interactive
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Put dc into interactive mode. See the man page for more details.
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-L --no-line-length
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Disable line length checking.
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-O obase --obase=obase
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Sets the builtin variable obase to the given value assuming that the given
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value is in base 10. It is a fatal error if the given value is not a valid
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number.
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-P --no-prompt
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Disable the prompts in interactive mode.
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-R --no-read-prompt
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Disable the read prompt in interactive mode.
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-S scale --scale=scale
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Sets the builtin variable scale to the given value assuming that the given
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value is in base 10. It is a fatal error if the given value is not a valid
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number.
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-V --version
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Print version and copyright and exit.
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-x --extended-register
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Enable extended register mode.
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-z --leading-zeroes
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Enable leading zeroes on numbers greater than -1 and less than 1.
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Environment variables:
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DC_ENV_ARGS
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Command-line arguments to use on every run.
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DC_LINE_LENGTH
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If an integer, the number of characters to print on a line before
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wrapping. Using 0 will disable line length checking.
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DC_SIGINT_RESET
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If an integer and non-zero, reset on SIGINT, rather than exit, when in
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interactive mode.
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If zero, do not reset on SIGINT in all cases, but exit instead.
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Overrides the default, which is %s.
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DC_TTY_MODE
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If an integer and non-zero, enable TTY mode when it is available.
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If zero, disable TTY mode in all cases.
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Overrides the default, which is TTY mode %s.
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DC_PROMPT
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If an integer and non-zero, enable prompt when TTY mode is possible.
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If zero, disable prompt in all cases.
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Overrides the default, which is prompt %s.
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DC_EXPR_EXIT
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If an integer and non-zero, exit when expressions or expression files are
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given on the command-line, and does not exit when an integer and zero.
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Overrides the default, which is %s.
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DC_DIGIT_CLAMP
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If an integer and non-zero, clamp digits larger than or equal to the
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current ibase when parsing numbers.
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Overrides the default, which is %s.
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