diff --git a/share/completions/doas.fish b/share/completions/doas.fish
index 411d67a41..e56071ec4 100644
--- a/share/completions/doas.fish
+++ b/share/completions/doas.fish
@@ -24,7 +24,7 @@ end
 function __fish_complete_doas_subcommand
     set -l args (__fish_doas_print_remaining_args)
     set -lx -a PATH /usr/local/sbin /sbin /usr/sbin
-    complete -C"$args"
+    complete -C "$args"
 end
 
 complete -c doas -n "not __fish_doas_print_remaining_args" -s a -d "Choose auth method on systems using /etc/login.conf"
diff --git a/share/completions/su.fish b/share/completions/su.fish
index 83115209b..410f22c19 100644
--- a/share/completions/su.fish
+++ b/share/completions/su.fish
@@ -2,7 +2,7 @@
 
 complete -x -c su -a "(__fish_complete_users)"
 complete -c su -s l -l login -d "Make login shell"
-complete -r -c su -s c -l command -d "Pass command to shell" -xa "(complete -C(commandline -ct))"
+complete -c su -s c -l command -d "Pass command to shell" -xa "(__fish_complete_external_command)"
 complete -c su -s f -l fast -d "Pass -f to the shell"
 complete -c su -s m -l preserve_environment -d "Preserve environment"
 complete -c su -s p -d "Preserve environment"
diff --git a/share/completions/sudo.fish b/share/completions/sudo.fish
index f092fddce..f432b5334 100644
--- a/share/completions/sudo.fish
+++ b/share/completions/sudo.fish
@@ -34,7 +34,7 @@ end
 function __fish_complete_sudo_subcommand
     set -l args (__fish_sudo_print_remaining_args)
     set -lx -a PATH /usr/local/sbin /sbin /usr/sbin
-    complete -C"$args"
+    complete -C "$args"
 end
 
 # All these options should be valid for GNU and OSX sudo
diff --git a/share/completions/svn.fish b/share/completions/svn.fish
index 6590ac876..7e02653d3 100644
--- a/share/completions/svn.fish
+++ b/share/completions/svn.fish
@@ -172,7 +172,7 @@ for cmd in $blame $diff $log $merge
 end
 
 for cmd in $cleanup $merge $switch $update
-    _svn_cmpl_ $cmd -l diff3-cmd -d 'Use as merge command' -xa "(complete -C(commandline -ct))"
+    _svn_cmpl_ $cmd -l diff3-cmd -d 'Use as merge command' -xa "(__fish_complete_external_command)"
 end
 
 for cmd in $blame $info $list $log $stat
@@ -193,7 +193,7 @@ end
 
 for cmd in $diff $log
     _svn_cmpl_ $cmd -l internal-diff -d 'Override diff-cmd specified in config file'
-    _svn_cmpl_ $cmd -l diff-cmd -d 'Use external diff command' -xa "(complete -C(commandline -ct))"
+    _svn_cmpl_ $cmd -l diff-cmd -d 'Use external diff command' -xa "(__fish_complete_external_command)"
 end
 
 for cmd in $add $import
diff --git a/share/completions/type.fish b/share/completions/type.fish
index e9598c7f0..e58ba1de2 100644
--- a/share/completions/type.fish
+++ b/share/completions/type.fish
@@ -10,4 +10,4 @@ complete -c type -s q -l quiet -d "Suppress output"
 complete -c type -a "(builtin -n)" -d "Builtin"
 complete -c type -a "(functions -n)" -d "Function"
 
-complete -c type -a "(complete -C(commandline -ct))" -x
+complete -c type -a "(__fish_complete_command)" -x
diff --git a/share/completions/which.fish b/share/completions/which.fish
index d6c6decef..1b54defc9 100644
--- a/share/completions/which.fish
+++ b/share/completions/which.fish
@@ -16,4 +16,4 @@ else # OSX
     complete -c which -s s -d "Print no output, only return 0 if found"
 end
 
-complete -c which -a "(complete -C(commandline -ct))" -x
+complete -c which -a "(__fish_complete_external_command)" -x
diff --git a/share/completions/xterm.fish b/share/completions/xterm.fish
index 036d0643e..b8c254d73 100644
--- a/share/completions/xterm.fish
+++ b/share/completions/xterm.fish
@@ -98,7 +98,7 @@ complete -c xterm -o wc -d 'Use wide characters'
 complete -c xterm -o wf -d 'Wait the first time for the window to be mapped'
 complete -c xterm -o Sccn -d 'Use as input/output channel for an existing program'
 
-complete -c xterm -s e -a "(complete -C(commandline -ct))" -x -d 'Run program in xterm'
+complete -c xterm -s e -a "(__fish_complete_external_command)" -x -d 'Run program in xterm'
 
 complete -r -c xterm -o bcf -d 'Blinking cursor will be off for that many milliseconds'
 complete -r -c xterm -o bcn -d 'Blinking cursor will be on for that many milliseconds'
diff --git a/share/functions/__fish_complete_command.fish b/share/functions/__fish_complete_command.fish
index f6cc7e20a..ddbfb0273 100644
--- a/share/functions/__fish_complete_command.fish
+++ b/share/functions/__fish_complete_command.fish
@@ -3,8 +3,10 @@ function __fish_complete_command --description 'Complete using all available com
     switch $ctoken
         case '*=*'
             set ctoken (string split "=" -- $ctoken)
-            printf '%s\n' $ctoken[1]=(complete -C$ctoken[2])
+            printf '%s\n' $ctoken[1]=(complete -C "$ctoken[2]")
+        case '-*' # do not try to complete options as commands
+            return
         case '*'
-            complete -C$ctoken
+            complete -C "$ctoken"
     end
 end
diff --git a/share/functions/__fish_complete_external_command.fish b/share/functions/__fish_complete_external_command.fish
index 218aee4f3..2790c61e7 100644
--- a/share/functions/__fish_complete_external_command.fish
+++ b/share/functions/__fish_complete_external_command.fish
@@ -1,3 +1,3 @@
 function __fish_complete_external_command
-    command find $PATH/ -maxdepth 1 -perm +u+x 2>&- | string match -r '[^/]*$'
+    command find $PATH/ -maxdepth 1 -perm -u+x 2>&- | string match -r '[^/]*$'
 end
diff --git a/share/functions/__fish_complete_subcommand.fish b/share/functions/__fish_complete_subcommand.fish
index 9f5ac1d59..79496d6d2 100644
--- a/share/functions/__fish_complete_subcommand.fish
+++ b/share/functions/__fish_complete_subcommand.fish
@@ -39,7 +39,7 @@ function __fish_complete_subcommand -d "Complete subcommand" --no-scope-shadowin
         end
     end
 
-    printf "%s\n" (complete -C$res)
+    printf "%s\n" (complete -C "$res")
 
 end