Zbigniew Jędrzejewski-Szmek
58e7959988
This allows multi-call binaries to be easily invoked with a different name. After installation, the name is set by creating a symlink. But in build directories, we don't create the symlinks. (There are also other ways to achieve the same thing, e.g. zsh supports $ARGV0, and exec -a can be used, but those are either non-portable or are more complicated to use.) The primary use-case for me is to test --help output for multicall binaries. Also reorder the help for env vars to group the more generic ones near the top. This was initially proposed in https://github.com/systemd/systemd/pull/24054, but there were some comments about the implementation. I had a branch with the patch, but I don't think I ever actually submitted it as a pull request.
75 lines
2.6 KiB
C
75 lines
2.6 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <stdlib.h>
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#include "alloc-util.h"
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#include "ansi-color.h"
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#include "help-util.h"
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#include "path-util.h"
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#include "pretty-print.h"
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/* These are helpers for putting together --help texts in a uniform way with a common output style. Each
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* function generates a separate part of the --help text:
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*
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* 1. help_cmdline() outputs a brief summary of the command line syntax. This shall be used at least once,
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* in some cases multiple times. This generally comes first in the output.
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*
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* 2. help_abstract() outputs a brief prose abstract of the command, should carry a single line of text
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* that gives the user a hint what this tool does. Use only once, right after the last help_cmdline().
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*
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* 3. help_section() can be used to format multiple sections of the --help text. It should be used at least
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* once for an "Options:" section, but can be used more than once, for programs with many
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* options/verbs. The first invocation should come right after help_abstract().
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*
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* 4. Finally, help_man_page_reference() adds a final line linking the man page of the tool. This should be
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* used only once, and terminates the --help text.
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*
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* Switches and verbs documentation should be inserted after each help_section(). For that ideally use
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* options.[ch] APIs. */
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void help_cmdline(const char *arguments) {
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const char *progname =
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last_path_component(secure_getenv("SYSTEMD_INVOKED_AS"))
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?: program_invocation_short_name;
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assert(arguments);
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printf("%s>%s %s %s\n",
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ansi_grey(),
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ansi_normal(),
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progname,
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arguments);
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}
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void help_abstract(const char *text) {
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assert(text);
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printf("\n%s%s%s%s\n",
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ansi_highlight(),
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ansi_add_italics(),
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text,
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ansi_normal());
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}
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void help_section(const char *title) {
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assert(title);
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printf("\n%s%s:%s\n",
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ansi_underline(),
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title,
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ansi_normal());
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}
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void help_man_page_reference(const char *page, const char *section) {
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assert(page);
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assert(section);
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/* Displaying --help texts generally should not fail, hence let's fall back to a simple string in
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* case of OOM. */
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_cleanup_free_ char *link = NULL;
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if (terminal_urlify_man(page, section, &link) < 0)
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printf("\nSee the %s(%s) man page for details.\n", page, section);
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else
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printf("\nSee the %s for details.\n", link);
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}
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