diff --git a/share/completions/and.fish b/share/completions/and.fish
index 9066e6101..50d2825b6 100644
--- a/share/completions/and.fish
+++ b/share/completions/and.fish
@@ -1,3 +1,3 @@
 complete -c and -s h -l help -d 'Display help and exit'
-complete -c and -xa '( __fish_complete_subcommand )'
+complete -c and -xa '(__fish_complete_subcommand --allow-functions-and-builtins)'
 
diff --git a/share/completions/begin.fish b/share/completions/begin.fish
index e95aa4bbc..4d3c1256f 100644
--- a/share/completions/begin.fish
+++ b/share/completions/begin.fish
@@ -1,2 +1,2 @@
 complete -c begin -s h -l help -d 'Display help and exit'
-complete -c begin -xa '(__fish_complete_subcommand)'
+complete -c begin -xa '(__fish_complete_subcommand --allow-functions-and-builtins)'
diff --git a/share/completions/command.fish b/share/completions/command.fish
index 7c3e6956b..85d4eca3a 100644
--- a/share/completions/command.fish
+++ b/share/completions/command.fish
@@ -3,5 +3,4 @@ complete -c command -n 'test (count (commandline -opc)) -eq 1' -s a -l all -d 'P
 complete -c command -n 'test (count (commandline -opc)) -eq 1' -s q -l quiet -d 'Do not print anything, only set exit status'
 complete -c command -n 'test (count (commandline -opc)) -eq 1' -s s -l search -d 'Print the file that would be executed'
 complete -c command -n 'test (count (commandline -opc)) -eq 1' -s s -l search -d 'Print the file that would be executed'
-complete -c command -n 'test (count (commandline -opc)) -eq 1' -xa "(__fish_complete_external_command)"
-complete -c command -n 'test (count (commandline -opc)) -ge 2' -xa "(__fish_complete_subcommand)"
+complete -c command -xa "(__fish_complete_subcommand)"
diff --git a/share/completions/doas.fish b/share/completions/doas.fish
index e56071ec4..e90cf7730 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"
+    __fish_complete_subcommand --commandline $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/env.fish b/share/completions/env.fish
index 1de054afd..370cd3fed 100644
--- a/share/completions/env.fish
+++ b/share/completions/env.fish
@@ -17,7 +17,7 @@ function __fish_complete_env_subcommand
 
     # Then complete the rest as if it was given as a command.
     if test -n "$argv"
-        complete -C "$argv"
+        __fish_complete_subcomand --commandline $argv
         return 0
     end
     return 1
diff --git a/share/completions/exec.fish b/share/completions/exec.fish
index 1123f1e3e..73b535ee0 100644
--- a/share/completions/exec.fish
+++ b/share/completions/exec.fish
@@ -1,3 +1,2 @@
 complete -c exec -n 'test (count (commandline -opc)) -eq 1' -s h -l help -d 'Display help and exit'
-complete -c exec -n 'test (count (commandline -opc)) -eq 1' -xa "(__fish_complete_external_command)"
-complete -c exec -n 'test (count (commandline -opc)) -ge 2' -xa "(__fish_complete_subcommand)"
+complete -c exec -xa "(__fish_complete_subcommand)"
diff --git a/share/completions/if.fish b/share/completions/if.fish
index 978b1868d..5a2c2bdd4 100644
--- a/share/completions/if.fish
+++ b/share/completions/if.fish
@@ -1,2 +1,2 @@
 complete -c if -s h -l help -d 'Display help and exit'
-complete -c if -xa '(__fish_complete_subcommand)'
+complete -c if -xa '(__fish_complete_subcommand --allow-functions-and-builtins)'
diff --git a/share/completions/mosh.fish b/share/completions/mosh.fish
index 36a00b36f..2185d24da 100644
--- a/share/completions/mosh.fish
+++ b/share/completions/mosh.fish
@@ -4,7 +4,7 @@ complete -x -c mosh -d Hostname -a "(__fish_complete_user_at_hosts)"
 complete -x -c mosh -d User -a "
 (__fish_print_users)@
 "
-complete -c mosh -d "Command to run" -x -a '(__fish_complete_subcommand --fcs-skip=2)'
+complete -c mosh -n 'test (__fish_number_of_cmd_args_wo_opts) -ge 2' -d "Command to run" -x -a '(__fish_complete_subcommand --fcs-skip=2)'
 
 complete -c mosh -l client -d 'Path to client helper on local machine (default: "mosh-client")'
 complete -c mosh -l server -d 'Command to run server helper on remote machine (default: "mosh-server")'
diff --git a/share/completions/not.fish b/share/completions/not.fish
index 90fa69045..f77344e86 100644
--- a/share/completions/not.fish
+++ b/share/completions/not.fish
@@ -1,2 +1,2 @@
 complete -c not -s h -l help -d 'Display help and exit'
-complete -c not -xa '(__fish_complete_subcommand)'
+complete -c not -xa '(__fish_complete_subcommand --allow-functions-and-builtins)'
diff --git a/share/completions/or.fish b/share/completions/or.fish
index d95e0957d..2c081c22d 100644
--- a/share/completions/or.fish
+++ b/share/completions/or.fish
@@ -1,3 +1,3 @@
 
 complete -c or -s h -l help -d 'Display help and exit'
-complete -c or -xa '(__fish_complete_subcommand)'
+complete -c or -xa '(__fish_complete_subcommand --allow-functions-and-builtins)'
diff --git a/share/completions/ssh.fish b/share/completions/ssh.fish
index f2becec78..6bbc57118 100644
--- a/share/completions/ssh.fish
+++ b/share/completions/ssh.fish
@@ -13,7 +13,7 @@ complete -x -c ssh -d "Remote" -a "(__fish_complete_user_at_hosts)"
 # (__fish_print_users | string match -r -v '^_')@
 # "
 
-complete -c ssh -d "Command to run" -x -a '(__fish_complete_subcommand --fcs-skip=2)'
+complete -c ssh -n 'test (__fish_number_of_cmd_args_wo_opts) -ge 2' -d "Command to run" -x -a '(__fish_complete_subcommand --fcs-skip=2)'
 
 complete -c ssh -s a -d "Disables forwarding of the authentication agent"
 complete -c ssh -s A -d "Enables forwarding of the authentication agent"
diff --git a/share/completions/sudo.fish b/share/completions/sudo.fish
index f432b5334..24abb0cce 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"
+    __fish_complete_subcommand --commandline $args
 end
 
 # All these options should be valid for GNU and OSX sudo
diff --git a/share/completions/while.fish b/share/completions/while.fish
index d85e72092..d799cf9ec 100644
--- a/share/completions/while.fish
+++ b/share/completions/while.fish
@@ -1,2 +1,2 @@
 complete -c while -s h -l help -d 'Display help and exit'
-complete -c while -xa '(__fish_complete_subcommand)'
+complete -c while -xa '(__fish_complete_subcommand --allow-functions-and-builtins)'
diff --git a/share/functions/__fish_complete_subcommand.fish b/share/functions/__fish_complete_subcommand.fish
index 79496d6d2..d67c009a5 100644
--- a/share/functions/__fish_complete_subcommand.fish
+++ b/share/functions/__fish_complete_subcommand.fish
@@ -1,45 +1,58 @@
 function __fish_complete_subcommand -d "Complete subcommand" --no-scope-shadowing
+    # Pass --commandline to complete the remainder of the arguments instead of the commandline.
+    # Pass --allow-functions-and-builtins to enable the completion of the first token as function or builtin.
+    # Other args are considered flags to the supercommand that require an option.
+
+    # How many non-option tokens we skip in the input commandline before completing the subcommand
+    # Usually 1; for ssh 2.
     set -l skip_next 1
-    set -l test
-    switch "$argv[1]"
-        case '--fcs-skip=*'
-            set -l rest
-            string replace -a = ' ' -- $argv[1] | read test skip_next
-            set -e argv[1]
-    end
-
-    set -l res ""
-    set -l had_cmd 0
-    set -l cmd (commandline -cop) (commandline -ct)
-
-    for i in $cmd
-
-        if test $skip_next -gt 0
-            set skip_next (math $skip_next - 1)
-            continue
+    set -l allow_functions_and_builtins false
+    set -l subcommand
+    while string match -rq -- '^--[a-z]' $argv[1]
+        set -l arg $argv[1]
+        set -e argv[1]
+        switch $arg
+            case '--fcs-skip=*'
+                set skip_next (string split = -- $arg)[2]
+            case '--allow-functions-and-builtins'
+                set allow_functions_and_builtins true
+            case '--commandline'
+                set subcommand $argv
+                set -e argv
+                break
         end
+    end
+    set -l options_with_param $argv
 
-        if test "$had_cmd" = 1
-            set res "$res $i"
-        else
-
-            if contains -- $i $argv
+    if not string length -q $subcommand
+        set cmd (commandline -cop) (commandline -ct)
+        while set -q cmd[1]
+            set -l token $cmd[1]
+            set -e cmd[1]
+            if contains -- $token $options_with_param
                 set skip_next (math $skip_next + 1)
                 continue
             end
-
-            switch $i
-                case '-*'
-                case '*=*'
+            switch $token
+                case '-*' '*=*'
+                    continue
                 case '*'
-
-                    set had_cmd 1
-                    set res $i
+                    if test $skip_next -gt 0
+                        set skip_next (math $skip_next - 1)
+                        continue
+                    end
+                    # found the start of our command
+                    set subcommand $token $cmd
+                    break
             end
         end
     end
 
-    printf "%s\n" (complete -C "$res")
+    if test $allow_functions_and_builtins = false && test (count $subcommand) -eq 1
+        __fish_complete_external_command
+    else
+        printf "%s\n" (complete -C "$subcommand")
+    end
 
 end