runtime(filetype): make shell filetype detection more robust
closes: #17063
Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/sh.vim b/runtime/syntax/sh.vim
index 2981982..9e5320f 100644
--- a/runtime/syntax/sh.vim
+++ b/runtime/syntax/sh.vim
@@ -9,6 +9,7 @@
" 2025 Jan 18 add bash coproc, remove duplicate syn keywords (#16467)
" 2025 Mar 21 update shell capability detection (#16939)
" 2025 Apr 03 command substitution opening paren at EOL (#17026)
+" 2025 Apr 10 improve shell detection (#17084)
" Version: 208
" Former URL: http://www.drchip.org/astronaut/vim/index.html#SYNTAX_SH
" For options and settings, please use: :help ft-sh-syntax
@@ -23,11 +24,13 @@
let b:is_sh = 1
" If the shell script itself specifies which shell to use, use it
-if getline(1) =~ '\<ksh\>'
+let s:shebang = getline(1)
+
+if s:shebang =~ '^#!.\{-2,}\<ksh\>'
let b:is_kornshell = 1
-elseif getline(1) =~ '\<bash\>'
+elseif s:shebang =~ '^#!.\{-2,}\<bash\>'
let b:is_bash = 1
-elseif getline(1) =~ '\<dash\>'
+elseif s:shebang =~ '^#!.\{-2,}\<dash\>'
let b:is_dash = 1
" handling /bin/sh with is_kornshell/is_sh {{{1
" b:is_sh will be set when "#! /bin/sh" is found;
@@ -70,6 +73,8 @@
endif
endif
+unlet s:shebang
+
" if b:is_dash, set b:is_posix too
if exists("b:is_dash")
let b:is_posix= 1