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Diffstat (limited to 'src/echo.c')
| -rw-r--r-- | src/echo.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/src/echo.c b/src/echo.c new file mode 100644 index 0000000..1f2cbc7 --- /dev/null +++ b/src/echo.c @@ -0,0 +1,277 @@ +/* echo.c, derived from code echo.c in Bash. + Copyright (C) 1987-2022 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> +#include <stdio.h> +#include <assert.h> +#include <sys/types.h> +#include "system.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "echo" + +#define AUTHORS \ + proper_name ("Brian Fox"), \ + proper_name ("Chet Ramey") + +/* If true, interpret backslash escapes by default. */ +#ifndef DEFAULT_ECHO_TO_XPG +enum { DEFAULT_ECHO_TO_XPG = false }; +#endif + +void +usage (int status) +{ + /* STATUS should always be EXIT_SUCCESS (unlike in most other + utilities which would call emit_try_help otherwise). */ + assert (status == EXIT_SUCCESS); + + printf (_("\ +Usage: %s [SHORT-OPTION]... [STRING]...\n\ + or: %s LONG-OPTION\n\ +"), program_name, program_name); + fputs (_("\ +Echo the STRING(s) to standard output.\n\ +\n\ + -n do not output the trailing newline\n\ +"), stdout); + fputs (_(DEFAULT_ECHO_TO_XPG + ? N_("\ + -e enable interpretation of backslash escapes (default)\n\ + -E disable interpretation of backslash escapes\n") + : N_("\ + -e enable interpretation of backslash escapes\n\ + -E disable interpretation of backslash escapes (default)\n")), + stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + fputs (_("\ +\n\ +If -e is in effect, the following sequences are recognized:\n\ +\n\ +"), stdout); + fputs (_("\ + \\\\ backslash\n\ + \\a alert (BEL)\n\ + \\b backspace\n\ + \\c produce no further output\n\ + \\e escape\n\ + \\f form feed\n\ + \\n new line\n\ + \\r carriage return\n\ + \\t horizontal tab\n\ + \\v vertical tab\n\ +"), stdout); + fputs (_("\ + \\0NNN byte with octal value NNN (1 to 3 digits)\n\ + \\xHH byte with hexadecimal value HH (1 to 2 digits)\n\ +"), stdout); + printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME); + fputs (_("\n\ +NOTE: printf(1) is a preferred alternative,\n\ +which does not have issues outputting option-like strings.\n\ +"), stdout); + emit_ancillary_info (PROGRAM_NAME); + exit (status); +} + +/* Convert C from hexadecimal character to integer. */ +static int +hextobin (unsigned char c) +{ + switch (c) + { + default: return c - '0'; + case 'a': case 'A': return 10; + case 'b': case 'B': return 11; + case 'c': case 'C': return 12; + case 'd': case 'D': return 13; + case 'e': case 'E': return 14; + case 'f': case 'F': return 15; + } +} + +/* Print the words in LIST to standard output. If the first word is + '-n', then don't print a trailing newline. We also support the + echo syntax from Version 9 unix systems. */ + +int +main (int argc, char **argv) +{ + bool display_return = true; + bool posixly_correct = !!getenv ("POSIXLY_CORRECT"); + bool allow_options = + (! posixly_correct + || (! DEFAULT_ECHO_TO_XPG && 1 < argc && STREQ (argv[1], "-n"))); + + /* System V machines already have a /bin/sh with a v9 behavior. + Use the identical behavior for these machines so that the + existing system shell scripts won't barf. */ + bool do_v9 = DEFAULT_ECHO_TO_XPG; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + + /* We directly parse options, rather than use parse_long_options, in + order to avoid accepting abbreviations. */ + if (allow_options && argc == 2) + { + if (STREQ (argv[1], "--help")) + usage (EXIT_SUCCESS); + + if (STREQ (argv[1], "--version")) + { + version_etc (stdout, PROGRAM_NAME, PACKAGE_NAME, Version, AUTHORS, + (char *) NULL); + return EXIT_SUCCESS; + } + } + + --argc; + ++argv; + + if (allow_options) + while (argc > 0 && *argv[0] == '-') + { + char const *temp = argv[0] + 1; + size_t i; + + /* If it appears that we are handling options, then make sure that + all of the options specified are actually valid. Otherwise, the + string should just be echoed. */ + + for (i = 0; temp[i]; i++) + switch (temp[i]) + { + case 'e': case 'E': case 'n': + break; + default: + goto just_echo; + } + + if (i == 0) + goto just_echo; + + /* All of the options in TEMP are valid options to ECHO. + Handle them. */ + while (*temp) + switch (*temp++) + { + case 'e': + do_v9 = true; + break; + + case 'E': + do_v9 = false; + break; + + case 'n': + display_return = false; + break; + } + + argc--; + argv++; + } + +just_echo: + + if (do_v9 || posixly_correct) + { + while (argc > 0) + { + char const *s = argv[0]; + unsigned char c; + + while ((c = *s++)) + { + if (c == '\\' && *s) + { + switch (c = *s++) + { + case 'a': c = '\a'; break; + case 'b': c = '\b'; break; + case 'c': return EXIT_SUCCESS; + case 'e': c = '\x1B'; break; + case 'f': c = '\f'; break; + case 'n': c = '\n'; break; + case 'r': c = '\r'; break; + case 't': c = '\t'; break; + case 'v': c = '\v'; break; + case 'x': + { + unsigned char ch = *s; + if (! isxdigit (ch)) + goto not_an_escape; + s++; + c = hextobin (ch); + ch = *s; + if (isxdigit (ch)) + { + s++; + c = c * 16 + hextobin (ch); + } + } + break; + case '0': + c = 0; + if (! ('0' <= *s && *s <= '7')) + break; + c = *s++; + FALLTHROUGH; + case '1': case '2': case '3': + case '4': case '5': case '6': case '7': + c -= '0'; + if ('0' <= *s && *s <= '7') + c = c * 8 + (*s++ - '0'); + if ('0' <= *s && *s <= '7') + c = c * 8 + (*s++ - '0'); + break; + case '\\': break; + + not_an_escape: + default: putchar ('\\'); break; + } + } + putchar (c); + } + argc--; + argv++; + if (argc > 0) + putchar (' '); + } + } + else + { + while (argc > 0) + { + fputs (argv[0], stdout); + argc--; + argv++; + if (argc > 0) + putchar (' '); + } + } + + if (display_return) + putchar ('\n'); + return EXIT_SUCCESS; +} |