How can I check if Vim is 32 bit or 64 bit? (On Linux!)

Question

How can I find out if the vim I'm using is 32 or 64 bit? I'm using Ubuntu so this doesn't apply to me, I think. Also I checked

:version

and got this output:

VIM - Vi IMproved 7.3 (2010 Aug 15, compiled May  4 2012 04:21:49)
Inklusive der Korrekturen: 1-429
Verändert von pkg-vim-maintainers@lists.alioth.debian.org
Übersetzt von buildd@
Riesige Version mit GTK2 GUI. Ein- (+) oder ausschließlich (-) der Eigenschaften:
+arabic +autocmd +balloon_eval +browse ++builtin_terms +byte_offset +cindent +clientserver +clipboard +cmdline_compl +cmdline_hist +cmdline_info
 +comments +conceal +cryptv +cscope +cursorbind +cursorshape +dialog_con_gui +diff +digraphs +dnd -ebcdic +emacs_tags +eval +ex_extra
+extra_search +farsi +file_in_path +find_in_path +float +folding -footer +fork() +gettext -hangul_input +iconv +insert_expand +jumplist +keymap
+langmap +libcall +linebreak +lispindent +listcmds +localmap +lua +menu +mksession +modify_fname +mouse +mouseshape +mouse_dec +mouse_gpm
-mouse_jsbterm +mouse_netterm -mouse_sysmouse +mouse_xterm +mouse_urxvt +multi_byte +multi_lang -mzscheme +netbeans_intg +path_extra +perl
+persistent_undo +postscript +printer +profile +python -python3 +quickfix +reltime +rightleft +ruby +scrollbind +signs +smartindent -sniff
+startuptime +statusline -sun_workshop +syntax +tag_binary +tag_old_static -tag_any_white +tcl +terminfo +termresponse +textobjects +title
+toolbar +user_commands +vertsplit +virtualedit +visual +visualextra +viminfo +vreplace +wildignore +wildmenu +windows +writebackup +X11
-xfontset +xim +xsmp_interact +xterm_clipboard -xterm_save
          System-vimrc-Datei: "$VIM/vimrc"
        Benutzer-vimrc-Datei: "$HOME/.vimrc"
         Benutzer-exrc-Datei: "$HOME/.exrc"
         System-gvimrc-Datei: "$VIM/gvimrc"
       Benutzer-gvimrc-Datei: "$HOME/.gvimrc"
           System-Menü-Datei: "$VIMRUNTIME/menu.vim"
     Voreinstellung für $VIM: "/usr/share/vim"
Übersetzt: gcc -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_GTK  -pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/
include/atk-1.0 -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/glib-2.0
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12     -g -O2 -fstack-protecto
r --param=ssp-buffer-size=4 -Wformat -Wformat-security -Werror=format-security -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1     -I/usr/include/tcl8.5  -
D_REENTRANT=1  -D_THREAD_SAFE=1  -D_LARGEFILE64_SOURCE=1
Linken: gcc   -L. -Wl,-Bsymbolic-functions -Wl,-z,relro -rdynamic -Wl,-export-dynamic  -Wl,-E  -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,--as-nee
ded -o vim   -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lcairo -lpango-1.0 -lfreetype -lfo
ntconfig -lgobject-2.0 -lglib-2.0   -lSM -lICE -lXpm -lXt -lX11 -lXdmcp -lSM -lICE -lm -ltinfo -lnsl  -lselinux  -lacl -lattr -lgpm -ldl  -L/usr/
lib -llua5.1  -Wl,-E  -fstack-protector -L/usr/local/lib  -L/usr/lib/perl/5.14/CORE -lperl -ldl -lm -lpthread -lcrypt -L/usr/lib/python2.7/config
 -lpython2.7 -lpthread -ldl -lutil -lm -Xlinker -export-dynamic -Wl,-O1 -Wl,-Bsymbolic-functions  -L/usr/lib -ltcl8.5 -ldl -lpthread -lieee -lm -
lruby1.8 -lpthread -lrt -ldl -lcrypt -lm  -L/usr/lib

but it doesn't look like it tells me what I want to know.

Answer 1

Since you're on Ubuntu, use the file command:

$ file -L "$(command -v vim)"
/usr/bin/vim.gnome: ELF 64-bit LSB  shared object, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=acb723f1249782755116f93ed45a30e7115ff423, stripped

As you can see, my vim is 64-bit.

We need to use -L since /usr/bin/vim on Ubuntu is a symlink, managed by the Debian alternatives system, and GNU file by default doesn't follow symlinks (thanks to Random832 for pointing this out!).

Or you can check the package architecture:

$ dpkg-query -f '${Package;10}\t${Architecture}\n' -W vim vim-gnome
       vim  amd64
 vim-gnome  amd64

---

Both of the above commands check the default vim as Carpetsmoker notes. Within Vim, you can do something like:

if system('file -L "' . exepath(v:progpath) . '"') =~ "64-bit"
    echo "yes"
endif

Or we can use Carpetsmoker's suggestion of the /proc/$PID/exe special link, which should be the most portable across Linux systems:

if system('file -L /proc/' . getpid() . '/exe' ) =~ "64-bit"
    echo "yes"
endif

---

/proc/$PID/exe is special. You can obtain the original executable for that process from /proc/$PID/exe even if it has been deleted, moved or replaced. In such cases, the output of readlink or resolve() on it may not be what you expect. For example, using a temporary copy of bash for illustration:

$ readlink  -f /proc/$$/exe
/tmp/bash (deleted)
$ file "$(readlink -f /proc/$$/exe)"
/tmp/bash (deleted): ERROR: cannot open `/tmp/bash (deleted)' (No such file or directory)

However, instructing file to follow the symlink, or using file - < /proc/self/exe to read directly from it, which works fine:

$ file -L /proc/$$/exe
/proc/10958/exe: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=b73723270773c893cf697d20c8d698f86a51635d, stripped
$ file - < /proc/self/exe
/dev/stdin: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=b73723270773c893cf697d20c8d698f86a51635d, stripped

We can't use the /proc/self/exe shortcut in Vim's call to system(), or as an argument to file, since then self will refer to the shell used to execute the command (if we used file - </proc/self/exe), or to file itself (if we used file -L /proc/self/exe). We could use /proc/self/exe if we were to read the file from Vim directly - which is what Carpetsmoker's answer does.

Answer 2

A "pure" Vim way, just because we can:

:let is_64_bits = match(strpart(readfile(resolve('/proc/' . getpid() . '/exe'), 'b', 1)[0], 4, 1), '\%x02') != -1

So, how does it work? Split up in multiple commands:

1. Get the path to the Vim binary:

   :let file = resolve('/proc/' . getpid() . '/exe')
   

2. Read the first "line" of the current binary. Reading a "line" makes little sense for binary files, but AFAIK I can't tell Vim to read a n number of bytes:

   :let contents = readfile(file, 'b', 1)[0]
   

3. Get the fifth byte:

   :let magic = strpart(contents, 4, 1)
   

4. Check if this byte matches 0x02, if it does, it's a 64-bit binary. Using == '\%x02' or =~ '\%x02' doesn't seem to work, so we use match().

   :let is_64_bits = match(magic, '\%x02') != -1
   

   I got the "magic" byte value from the magic file that the file command uses:

   0   string      \177ELF     ELF
   !:strength *2
   >4  byte        0       invalid class
   >4  byte        1       32-bit
   >4  byte        2       64-bit
   

Note that just using file as per muru's answer is probably better; I'm not sure if this works on all platforms/architectures (although a casual reading of the magic file suggests it would). I was mostly just curious to see if this could be done from within VimScript without any external tools ;-)