Unix & Linux Asked on January 8, 2021
I have several utility programs that do not have their own directory and are just a single executable. Typically I put the binary in /usr/local/bin. A problem I have is how to manage preference settings.
One idea is to use environment variables and require the user to define such variables, for example, in their bash.rc. I am a little reluctant, however, to clutter up the bash.rc with miscellaneous preference settings for a minor program.
Is there a Standard (or standard recommendation), that defines some place or method that is appropriate for storing preferences for small utility programs that do not have their own directory?
Where should small utility programs store their preferences?
This is a matter of opinion !
Is there a Standard (or standard recommendation),
And you should study for inspiration the source code and the documentation of several open source software. BTW the conventions for zsh are different of those for GNU bash and your login shell (often described in /etc/passwd, see passwd(5)) could be changed with chsh(1); I prefer to use zsh
When you compile one of them from its source code, you run a ./configure script (generated by GNU autoconf) and that script usually accepts some --help command.
As an example, for GNU emacs, ./configure --help gives
`configure' configures GNU Emacs 28.0.50 to adapt to many kinds of systems.
Usage: ./configure [OPTION]... [VAR=VALUE]...
To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE. See below for descriptions of some of the useful variables.
Defaults for the options are specified in brackets.
Configuration:
-h, --help display this help and exit
--help=short display options specific to this package
--help=recursive display the short help of all the included packages
-V, --version display version information and exit
-q, --quiet, --silent do not print `checking ...' messages
--cache-file=FILE cache test results in FILE [disabled]
-C, --config-cache alias for `--cache-file=config.cache'
-n, --no-create do not create output files
--srcdir=DIR find the sources in DIR [configure dir or `..']
Installation directories:
--prefix=PREFIX install architecture-independent files in PREFIX
[/usr/local]
--exec-prefix=EPREFIX install architecture-dependent files in EPREFIX
[PREFIX]
By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc. You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.
For better control, use the options below.
Fine tuning of the installation directories:
--bindir=DIR user executables [EPREFIX/bin]
--sbindir=DIR system admin executables [EPREFIX/sbin]
--libexecdir=DIR program executables [EPREFIX/libexec]
--sysconfdir=DIR read-only single-machine data [PREFIX/etc]
--sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com]
--localstatedir=DIR modifiable single-machine data [PREFIX/var]
--runstatedir=DIR modifiable per-process data [LOCALSTATEDIR/run]
--libdir=DIR object code libraries [EPREFIX/lib]
--includedir=DIR C header files [PREFIX/include]
--oldincludedir=DIR C header files for non-gcc [/usr/include]
--datarootdir=DIR read-only arch.-independent data root [PREFIX/share]
--datadir=DIR read-only architecture-independent data [DATAROOTDIR]
--infodir=DIR info documentation [DATAROOTDIR/info]
--localedir=DIR locale-dependent data [DATAROOTDIR/locale]
--mandir=DIR man documentation [DATAROOTDIR/man]
--docdir=DIR documentation root [DATAROOTDIR/doc/emacs]
--htmldir=DIR html documentation [DOCDIR]
--dvidir=DIR dvi documentation [DOCDIR]
--pdfdir=DIR pdf documentation [DOCDIR]
--psdir=DIR ps documentation [DOCDIR]
Program names:
--program-prefix=PREFIX prepend PREFIX to installed program names
--program-suffix=SUFFIX append SUFFIX to installed program names
--program-transform-name=PROGRAM run sed PROGRAM on installed program names
X features:
--x-includes=DIR X include files are in DIR
--x-libraries=DIR X library files are in DIR
System types:
--build=BUILD configure for building on BUILD [guessed]
--host=HOST cross-compile to build programs to run on HOST [BUILD]
Optional Features:
--disable-option-checking ignore unrecognized --enable/--with options
--disable-FEATURE do not include FEATURE (same as --enable-FEATURE=no)
--enable-FEATURE[=ARG] include FEATURE [ARG=yes]
--disable-ns-self-contained
disable self contained build under NeXTstep
--enable-locallisppath=PATH
directories Emacs should search for lisp files
specific to this site
--enable-checking[=LIST]
enable expensive checks. With LIST, enable only
specific categories of checks. Categories are:
all,yes,no. Flags are: stringbytes, stringoverrun,
stringfreelist, structs, glyphs
--enable-profiling build emacs with low-level, gprof profiling support.
Mainly useful for debugging Emacs itself. May not
work on all platforms. Stops profiler.el working.
--enable-autodepend automatically generate dependencies to .h-files.
Requires gcc, enabled if found.
--enable-gtk-deprecation-warnings
Show Gtk+/Gdk deprecation warnings for Gtk+ >= 3.0
--disable-build-details Make the build more deterministic by omitting host
names, time stamps, etc. from the output.
--disable-largefile omit support for large files
--enable-gcc-warnings[=TYPE]
control generation of GCC warnings. The TYPE 'yes'
means to fail if any warnings are issued;
'warn-only' means issue warnings without failing
(default for developer builds); 'no' means disable
warnings (default for non-developer builds).
--enable-check-lisp-object-type
Enable compile time checks for the Lisp_Object data
type, which can catch some bugs during development.
--enable-link-time-optimization
build with link-time optimization (experimental; see
INSTALL)
--disable-silent-rules verbose build output (undo: "make V=0")
--enable-cross-guesses={conservative|risky}
specify policy for cross-compilation guesses
--disable-acl do not support ACLs
Optional Packages:
--with-PACKAGE[=ARG] use PACKAGE [ARG=yes]
--without-PACKAGE do not use PACKAGE (same as --with-PACKAGE=no)
--without-all omit almost all features and build small executable
with minimal dependencies
--with-mailutils rely on GNU Mailutils, so that the --without-pop
through --with-mailhost options are irrelevant; this
is the default if GNU Mailutils is installed
--with-pop Support POP mail retrieval if Emacs movemail is used
(not recommended, as Emacs movemail POP is
insecure). This is the default only on native
MS-Windows.
--with-kerberos support Kerberos-authenticated POP
--with-kerberos5 support Kerberos version 5 authenticated POP
--with-hesiod support Hesiod to get the POP server host
--with-mail-unlink unlink, rather than empty, mail spool after reading
--with-mailhost=HOSTNAME
string giving default POP mail host
--with-sound=VALUE compile with sound support (VALUE one of: yes, alsa,
oss, bsd-ossaudio, no; default yes). Only for
GNU/Linux, FreeBSD, NetBSD, MinGW, Cygwin.
--with-pdumper=VALUE enable pdumper support unconditionally ('yes', 'no',
or 'auto': default 'auto')
--with-unexec=VALUE enable unexec support unconditionally ('yes', 'no',
or 'auto': default 'auto')
--with-dumping=VALUE kind of dumping to use for initial Emacs build
(VALUE one of: pdumper, unexec, none; default
pdumper)
--with-x-toolkit=KIT use an X toolkit (KIT one of: yes or gtk, gtk2,
gtk3, lucid or athena, motif, no)
--with-wide-int prefer wide Emacs integers (typically 62-bit); on
32-bit hosts, this allows buffer and string size up
to 2GB, at the cost of 10% to 30% slowdown of Lisp
interpreter and larger memory footprint
--without-xpm don't compile with XPM image support
--without-jpeg don't compile with JPEG image support
--without-tiff don't compile with TIFF image support
--without-gif don't compile with GIF image support
--without-png don't compile with PNG image support
--without-rsvg don't compile with SVG image support
--without-lcms2 don't compile with Little CMS support
--without-libsystemd don't compile with libsystemd support
--without-cairo don't compile with Cairo drawing
--without-xml2 don't compile with XML parsing support
--with-imagemagick compile with ImageMagick image support
--without-native-image-api
don't use native image APIs (GDI+ on Windows)
--with-json compile with native JSON support
--without-xft don't use XFT for anti aliased fonts
--without-harfbuzz don't use HarfBuzz for text shaping
--without-libotf don't use libotf for OpenType font support
--without-m17n-flt don't use m17n-flt for text shaping
--without-toolkit-scroll-bars
don't use Motif/Xaw3d/GTK toolkit scroll bars
--without-xaw3d don't use Xaw3d
--without-xim at runtime, default X11 XIM to off
--without-xdbe don't use X11 double buffering support
--with-ns use Nextstep (macOS Cocoa or GNUstep) windowing
system. On by default on macOS.
--with-w32 use native MS Windows GUI in a Cygwin build
--without-gpm don't use -lgpm for mouse support on a GNU/Linux
console
--without-dbus don't compile with D-Bus support
--with-gconf compile with Gconf support (Gsettings replaces this)
--without-gsettings don't compile with GSettings support
--without-selinux don't compile with SELinux support
--without-gnutls don't use -lgnutls for SSL/TLS support
--without-zlib don't compile with zlib decompression support
--without-modules don't compile with dynamic modules support
--without-threads don't compile with elisp threading support
--with-file-notification=LIB
use a file notification library (LIB one of: yes,
inotify, kqueue, gfile, w32, no)
--with-xwidgets enable use of xwidgets in Emacs buffers (requires
gtk3 or macOS Cocoa)
--without-makeinfo don't require makeinfo for building manuals
--without-compress-install
don't compress some files (.el, .info, etc.) when
installing. Equivalent to: make GZIP_PROG= install
--with-gameuser=USER_OR_GROUP
user for shared game score files. An argument
prefixed by ':' specifies a group instead.
--with-gnustep-conf=FILENAME
name of GNUstep configuration file to use on systems
where the command 'gnustep-config' does not work;
default $GNUSTEP_CONFIG_FILE, or
/etc/GNUstep/GNUstep.conf
--with-x use the X Window System
--without-libgmp do not use the GNU Multiple Precision (GMP) library;
this is the default on systems lacking libgmp.
--without-included-regex
don't compile regex; this is the default on systems
with recent-enough versions of the GNU C Library
(use with caution on other systems).
Some influential environment variables:
CC C compiler command
CFLAGS C compiler flags
LDFLAGS linker flags, e.g. -L<lib dir> if you have libraries in a
nonstandard directory <lib dir>
LIBS libraries to pass to the linker, e.g. -l<library>
CPPFLAGS (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
you have headers in a nonstandard directory <include dir>
CPP C preprocessor
PKG_CONFIG path to pkg-config utility
PKG_CONFIG_PATH
directories to add to pkg-config's search path
PKG_CONFIG_LIBDIR
path overriding pkg-config's built-in search path
ALSA_CFLAGS C compiler flags for ALSA, overriding pkg-config
ALSA_LIBS linker flags for ALSA, overriding pkg-config
XMKMF Path to xmkmf, Makefile generator for X Window System
OBJC Objective C compiler command
OBJCFLAGS Objective C compiler flags
RSVG_CFLAGS C compiler flags for RSVG, overriding pkg-config
RSVG_LIBS linker flags for RSVG, overriding pkg-config
IMAGEMAGICK_CFLAGS
C compiler flags for IMAGEMAGICK, overriding pkg-config
IMAGEMAGICK_LIBS
linker flags for IMAGEMAGICK, overriding pkg-config
GTK_CFLAGS C compiler flags for GTK, overriding pkg-config
GTK_LIBS linker flags for GTK, overriding pkg-config
WEBKIT_CFLAGS
C compiler flags for WEBKIT, overriding pkg-config
WEBKIT_LIBS linker flags for WEBKIT, overriding pkg-config
DBUS_CFLAGS C compiler flags for DBUS, overriding pkg-config
DBUS_LIBS linker flags for DBUS, overriding pkg-config
GSETTINGS_CFLAGS
C compiler flags for GSETTINGS, overriding pkg-config
GSETTINGS_LIBS
linker flags for GSETTINGS, overriding pkg-config
GCONF_CFLAGS
C compiler flags for GCONF, overriding pkg-config
GCONF_LIBS linker flags for GCONF, overriding pkg-config
GOBJECT_CFLAGS
C compiler flags for GOBJECT, overriding pkg-config
GOBJECT_LIBS
linker flags for GOBJECT, overriding pkg-config
LIBGNUTLS_CFLAGS
C compiler flags for LIBGNUTLS, overriding pkg-config
LIBGNUTLS_LIBS
linker flags for LIBGNUTLS, overriding pkg-config
LIBSYSTEMD_CFLAGS
C compiler flags for LIBSYSTEMD, overriding pkg-config
LIBSYSTEMD_LIBS
linker flags for LIBSYSTEMD, overriding pkg-config
JSON_CFLAGS C compiler flags for JSON, overriding pkg-config
JSON_LIBS linker flags for JSON, overriding pkg-config
KQUEUE_CFLAGS
C compiler flags for KQUEUE, overriding pkg-config
KQUEUE_LIBS linker flags for KQUEUE, overriding pkg-config
GFILENOTIFY_CFLAGS
C compiler flags for GFILENOTIFY, overriding pkg-config
GFILENOTIFY_LIBS
linker flags for GFILENOTIFY, overriding pkg-config
CAIRO_CFLAGS
C compiler flags for CAIRO, overriding pkg-config
CAIRO_LIBS linker flags for CAIRO, overriding pkg-config
FREETYPE_CFLAGS
C compiler flags for FREETYPE, overriding pkg-config
FREETYPE_LIBS
linker flags for FREETYPE, overriding pkg-config
FONTCONFIG_CFLAGS
C compiler flags for FONTCONFIG, overriding pkg-config
FONTCONFIG_LIBS
linker flags for FONTCONFIG, overriding pkg-config
XFT_CFLAGS C compiler flags for XFT, overriding pkg-config
XFT_LIBS linker flags for XFT, overriding pkg-config
LIBOTF_CFLAGS
C compiler flags for LIBOTF, overriding pkg-config
LIBOTF_LIBS linker flags for LIBOTF, overriding pkg-config
M17N_FLT_CFLAGS
C compiler flags for M17N_FLT, overriding pkg-config
M17N_FLT_LIBS
linker flags for M17N_FLT, overriding pkg-config
HARFBUZZ_CFLAGS
C compiler flags for HARFBUZZ, overriding pkg-config
HARFBUZZ_LIBS
linker flags for HARFBUZZ, overriding pkg-config
LCMS2_CFLAGS
C compiler flags for LCMS2, overriding pkg-config
LCMS2_LIBS linker flags for LCMS2, overriding pkg-config
PNG_CFLAGS C compiler flags for PNG, overriding pkg-config
PNG_LIBS linker flags for PNG, overriding pkg-config
XRANDR_CFLAGS
C compiler flags for XRANDR, overriding pkg-config
XRANDR_LIBS linker flags for XRANDR, overriding pkg-config
XINERAMA_CFLAGS
C compiler flags for XINERAMA, overriding pkg-config
XINERAMA_LIBS
linker flags for XINERAMA, overriding pkg-config
XFIXES_CFLAGS
C compiler flags for XFIXES, overriding pkg-config
XFIXES_LIBS linker flags for XFIXES, overriding pkg-config
LIBXML2_CFLAGS
C compiler flags for LIBXML2, overriding pkg-config
LIBXML2_LIBS
linker flags for LIBXML2, overriding pkg-config
Use these variables to override the choices made by `configure' or to help
it to find libraries and programs with nonstandard names/locations.
Report bugs to <[email protected]>.
GNU Emacs home page: <https://www.gnu.org/software/emacs/>.
General help using GNU software: <http://www.gnu.org/gethelp/>.
I often compile the latest GNU emacs snapshot. And I did:
'./configure' 'CC=gcc-10' 'CFLAGS=-O2 -g' '--program-suffix=-trunk'
'--prefix=/usr/local' '--sysconfdir=/etc/local'
which is kept in the config.status generated file.
BTW, to get the configuration options of your GCC just run gcc -v
E.g. Debian (or your favorite GNU/Linux distribution), and reading Linux From Scratch.
Read also Linux Filesystem Hierarchy Standard.
On other POSIX or Unix-like systems (e.g. Solaris or MacOSX) things are slightly different.
You could decide to pass options thru program options. Then see also this answer.
In several open source programs I am coding, I also document conventions about environment variables (see environ(7) and query them using getenv(3) ...) and I often decide to have a common prefix for them. So in the RefPerSys project (an open source symbolic artificial intelligence project) we are using of course REFPERSYS_, for example coding getenv("REFPERSYS_HOME") ... And in Bismon (a static analysis / software engineering tool funded by CHARIOT and DECODER European projects, see this draft report) the prefix is BISMON_
For graphical user interface applications, your favorite GUI framework (such as Qt or GTK) defines its own preferences.
You could easily embed Lua or GNU Guile (or Python) inside your programs coded in C or C++. These interpreters have each their own convention and syntax. The advantage of extending some existing interpreter is potential familiarity for advanced users of these scripting languages.
On Linux, a plugin is loaded by dlopen(3) and used thru dlsym(3) in programs coded in C or C++. If you accept them, please document the public API of your program.
Many major Linux programs (in particular the Firefox browser and the GCC compiler, but also GNU make or zsh) accept plugins. The advantage is that extensibility becomes easier, and the advanced user don't have to recompile some huge open source program to customize it. Another advantage is speed. However, learning a plugin API is a significant effort.
Answered by Basile Starynkevitch on January 8, 2021
Small utilities for interactive desktop use would be expected to follow the XDG Base Directory Specification and keep their config files under
$XDG_CONFIG_HOME
or (if that is empty or unset) default to
$HOME/.config
The picture is a little less clear for non-GUI tools, since they might run on systems which are headless or which don't otherwise adhere to XDG/freedesktop standards.
However, there's no obvious drawback to using $XDG_CONFIG_HOME if set or $HOME/.config if not, and it should be relatively unsurprising everywhere.
Answered by Useless on January 8, 2021
Although historically, a lot of programs used $HOME/.$PROGNAME the result is that home directories are becoming a bit messy. The preferred convention seems to be $HOME/.config/$PROGNAME nowadays (I currently have 173 dotfiles in ~, most of which are historical artefacts, and 80 in ~/.config).
Note that there is an important difference between config and preferences. The former is the system wide policy and should only be editable by root, while the latter should controlled by users. Preeferences should NOT be stored anywhere outside of $HOME.
Answered by symcbean on January 8, 2021
Opinion
You put the utilities into /usr/local/bin so you could reasonably use /usr/local/etc/{program_name} for system-wide settings, or $HOME/.{program_name} for local per-user configuration
In a shell script, since $0 contains the program name, these pathnames could be determined as "/usr/local/etc/${0##*/}" and "$HOME/.${0##*/}"
Answered by roaima on January 8, 2021
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