1/* 2 * ***************************************************************************** 3 * 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (c) 2018-2021 Gavin D. Howard and contributors. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions are met: 10 * 11 * * Redistributions of source code must retain the above copyright notice, this 12 * list of conditions and the following disclaimer. 13 * 14 * * Redistributions in binary form must reproduce the above copyright notice, 15 * this list of conditions and the following disclaimer in the documentation 16 * and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 * 30 * ***************************************************************************** 31 * 32 * The dc help text. 33 * 34 */ 35 36usage: %s [options] [file...] 37 38dc is a reverse-polish notation command-line calculator which supports unlimited 39precision arithmetic. For details, use `man %s`. 40 41This dc is (mostly) compatible with the FreeBSD dc and the GNU dc. See the 42FreeBSD man page (https://www.unix.com/man-page/FreeBSD/1/dc/) and the GNU dc 43manual (https://www.gnu.org/software/bc/manual/dc-1.05/html_mono/dc.html) for 44details. 45 46This dc has a few differences from the two above: 47 48 1) When printing a byte stream (command "P"), this bc follows what the FreeBSD 49 dc does. 50 2) This dc implements the GNU extensions for divmod ("~") and modular 51 exponentiation ("|"). 52 3) This dc implements all FreeBSD extensions, except for "J" and "M". 53 4) This dc does not implement the run command ("!"), for security reasons. 54 5) Like the FreeBSD dc, this dc supports extended registers. However, they are 55 implemented differently. When it encounters whitespace where a register 56 should be, it skips the whitespace. If the character following is not 57 a lowercase letter, an error is issued. Otherwise, the register name is 58 parsed by the following regex: 59 60 [a-z][a-z0-9_]* 61 62 This generally means that register names will be surrounded by whitespace. 63 64 Examples: 65 66 l idx s temp L index S temp2 < do_thing 67 68 Also note that, unlike the FreeBSD dc, extended registers are not even 69 parsed unless the "-x" option is given. Instead, the space after a command 70 that requires a register name is taken as the register name. 71 72Options: 73 74 -e expr --expression=expr 75 76 Run "expr" and quit. If multiple expressions or files (see below) are 77 given, they are all run. After running, dc will exit. 78 79 -f file --file=file 80 81 Run the dc code in "file" and exit. See above. 82 83 -h --help 84 85 Print this usage message and exit. 86 87 -i --interactive 88 89 Put dc into interactive mode. See the man page for more details. 90 91 -P --no-prompt 92 93 Disable the prompt in interactive mode. 94 95 -V --version 96 97 Print version and copyright and exit. 98 99 -x --extended-register 100 101 Enable extended register mode. 102