diff --git a/share/functions/__fish_complete_groups.fish b/share/functions/__fish_complete_groups.fish
index 5acc21290c72..2a3958cb6dd5 100644
--- a/share/functions/__fish_complete_groups.fish
+++ b/share/functions/__fish_complete_groups.fish
@@ -6,6 +6,6 @@ function __fish_complete_groups --description "Print a list of local groups, wit
     else
         while read -l line
             string split -f 1,4 : -- $line | string join \t
-        end </etc/group
+        end <?/etc/group
     end
 end
diff --git a/share/functions/__fish_complete_user_ids.fish b/share/functions/__fish_complete_user_ids.fish
index a48c1f740141..9c0371c1b5c9 100644
--- a/share/functions/__fish_complete_user_ids.fish
+++ b/share/functions/__fish_complete_user_ids.fish
@@ -1,7 +1,7 @@
 function __fish_complete_user_ids --description "Complete user IDs with user name as description"
     if command -sq getent
         getent passwd | string replace -f -r '^([[:alpha:]_][^:]*):[^:]*:(\d+).*' '$2\t$1'
-    else if test -r /etc/passwd
-        string replace -f -r '^([[:alpha:]_][^:]*):[^:]*:(\d+).*' '$2\t$1' </etc/passwd
+    else
+        string replace -f -r '^([[:alpha:]_][^:]*):[^:]*:(\d+).*' '$2\t$1' <?/etc/passwd
     end
 end
diff --git a/share/functions/__fish_complete_users.fish b/share/functions/__fish_complete_users.fish
index 6f6c29c62e96..7c0ca3777217 100644
--- a/share/functions/__fish_complete_users.fish
+++ b/share/functions/__fish_complete_users.fish
@@ -10,8 +10,8 @@ function __fish_complete_users --description "Print a list of local users, with
     else if command -sq dscl
         # This is the "Directory Service command line utility" used on macOS in place of getent.
         command dscl . -list /Users RealName | string match -r -v '^_' | string replace -r ' {2,}' \t
-    else if test -r /etc/passwd
-        string match -v -r '^\s*#' </etc/passwd | while read -l line
+    else
+        string match -v -r '^\s*#' <?/etc/passwd | while read -l line
             string split -f 1,5 : -- $line | string join \t | string replace -r ',.*' ''
         end
     end
diff --git a/share/functions/__fish_print_hostnames.fish b/share/functions/__fish_print_hostnames.fish
index 0c409aec77e4..219457740aaf 100644
--- a/share/functions/__fish_print_hostnames.fish
+++ b/share/functions/__fish_print_hostnames.fish
@@ -18,10 +18,8 @@ function __fish_print_hostnames -d "Print a list of known hostnames"
         string split ' '
 
     # Print nfs servers from /etc/fstab
-    if test -r /etc/fstab
-        string match -r '^\s*[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}:|^[a-zA-Z\.]*:' </etc/fstab |
-            string replace -r ':.*' ''
-    end
+    string match -r '^\s*[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}:|^[a-zA-Z\.]*:' <?/etc/fstab |
+    string replace -r ':.*' ''
 
     # Check hosts known to ssh.
     # Yes, seriously - the default specifies both with and without "2".
@@ -65,13 +63,11 @@ function __fish_print_hostnames -d "Print a list of known hostnames"
         function _recursive --no-scope-shadowing
             set -l paths
             for config in $argv
-                if test -r "$config" -a -f "$config"
-                    set paths $paths (
-                    # Keep only Include lines and remove Include syntax
-                    string replace -rfi '^\s*Include\s+' '' <$config \
-                    # Normalize whitespace
-                    | string trim | string replace -r -a '\s+' ' ')
-                end
+                set paths $paths (
+                # Keep only Include lines and remove Include syntax
+                string replace -rfi '^\s*Include\s+' '' <?$config \
+                # Normalize whitespace
+                | string trim | string replace -r -a '\s+' ' ')
             end
 
             set -l new_paths
@@ -117,9 +113,7 @@ function __fish_print_hostnames -d "Print a list of known hostnames"
 
     # Read all files and operate on their combined content
     for file in $known_hosts
-        if test -r $file
-            read -z <$file
-        end
+        read -z <?$file
     end |
         # Ignore hosts that are hashed, commented or @-marked and strip the key
         # Handle multiple comma-separated hostnames sharing a key, too.
diff --git a/share/functions/__fish_set_locale.fish b/share/functions/__fish_set_locale.fish
index dec2919ca1bf..75fd75b35478 100644
--- a/share/functions/__fish_set_locale.fish
+++ b/share/functions/__fish_set_locale.fish
@@ -26,15 +26,13 @@ function __fish_set_locale
     # but we operate under the assumption that the locale can't include whitespace. Other whitespace
     # shouldn't concern us, but a quoted "locale.LANG=SOMETHING" as a value to something else might.
     # Here the last definition of a variable takes precedence.
-    if test -r /proc/cmdline
-        for var in (string match -ra 'locale.[^=]+=\S+' < /proc/cmdline)
-            set -l kv (string replace 'locale.' '' -- $var | string split '=')
-            # Only set locale variables, not other stuff contained in these files - this also
-            # automatically ignores comments.
-            if contains -- $kv[1] $LOCALE_VARS
-                and set -q kv[2]
-                set -gx $kv[1] (string trim -c '\'"' -- $kv[2])
-            end
+    for var in (string match -ra 'locale.[^=]+=\S+' <?/proc/cmdline)
+        set -l kv (string replace 'locale.' '' -- $var | string split '=')
+        # Only set locale variables, not other stuff contained in these files - this also
+        # automatically ignores comments.
+        if contains -- $kv[1] $LOCALE_VARS
+            and set -q kv[2]
+            set -gx $kv[1] (string trim -c '\'"' -- $kv[2])
         end
     end
 
@@ -54,18 +52,16 @@ function __fish_set_locale
     # full POSIX-shell script.
     set -l user_cfg_dir (set -q XDG_CONFIG_HOME; and echo $XDG_CONFIG_HOME; or echo ~/.config)
     for f in $user_cfg_dir/locale.conf /etc/locale.conf /etc/env.d/02locale /etc/sysconfig/i18n /etc/default/locale
-        if test -r $f
-            while read -l kv
-                set kv (string split '=' -- $kv)
-                if contains -- $kv[1] $LOCALE_VARS
-                    and set -q kv[2]
-                    # Do not set already set variables again - this makes the merging happen.
-                    if not set -q $kv[1]
-                        set -gx $kv[1] (string trim -c '\'"' -- $kv[2])
-                    end
+        while read -l kv
+            set kv (string split '=' -- $kv)
+            if contains -- $kv[1] $LOCALE_VARS
+                and set -q kv[2]
+                # Do not set already set variables again - this makes the merging happen.
+                if not set -q $kv[1]
+                    set -gx $kv[1] (string trim -c '\'"' -- $kv[2])
                 end
-            end <$f
-        end
+            end
+        end <?$f
     end
 
     # If we really cannot get anything, at least set character encoding to UTF-8.
diff --git a/share/functions/fish_command_not_found.fish b/share/functions/fish_command_not_found.fish
index 36ca21905532..2d9e852a7003 100644
--- a/share/functions/fish_command_not_found.fish
+++ b/share/functions/fish_command_not_found.fish
@@ -5,11 +5,8 @@
 # This has a "ID=" line that defines the exact distribution,
 # and an "ID_LIKE=" line that defines what it is derived from or otherwise like.
 # For our purposes, we use both.
-set -l os
-if test -r /etc/os-release
-    set os (string match -r '^ID(?:_LIKE)?\s*=.*' < /etc/os-release | \
+set -l os (string match -r '^ID(?:_LIKE)?\s*=.*' <?/etc/os-release | \
     string replace -r '^ID(?:_LIKE)?\s*=(.*)' '$1' | string trim -c '\'"' | string split " ")
-end
 
 function __fish_default_command_not_found_handler
     printf (_ "fish: Unknown command: %s\n") (string escape -- $argv[1]) >&2
diff --git a/share/functions/fish_git_prompt.fish b/share/functions/fish_git_prompt.fish
index c8b55547fe25..f92d9761a339 100644
--- a/share/functions/fish_git_prompt.fish
+++ b/share/functions/fish_git_prompt.fish
@@ -478,9 +478,9 @@ function __fish_git_prompt_operation_branch_bare --description "fish_git_prompt
     set -l total
 
     if test -d $git_dir/rebase-merge
-        set branch (cat $git_dir/rebase-merge/head-name 2>/dev/null)
-        set step (cat $git_dir/rebase-merge/msgnum 2>/dev/null)
-        set total (cat $git_dir/rebase-merge/end 2>/dev/null)
+        read branch <?$git_dir/rebase-merge/head-name
+        read step <?$git_dir/rebase-merge/msgnum
+        read total <?$git_dir/rebase-merge/end
         if test -f $git_dir/rebase-merge/interactive
             set operation "|REBASE-i"
         else
@@ -488,10 +488,10 @@ function __fish_git_prompt_operation_branch_bare --description "fish_git_prompt
         end
     else
         if test -d $git_dir/rebase-apply
-            set step (cat $git_dir/rebase-apply/next 2>/dev/null)
-            set total (cat $git_dir/rebase-apply/last 2>/dev/null)
+            read step <?$git_dir/rebase-apply/next
+            read total <?$git_dir/rebase-apply/last
             if test -f $git_dir/rebase-apply/rebasing
-                set branch (cat $git_dir/rebase-apply/head-name 2>/dev/null)
+                read branch <?$git_dir/rebase-apply/head-name
                 set operation "|REBASE"
             else if test -f $git_dir/rebase-apply/applying
                 set operation "|AM"
diff --git a/share/functions/help.fish b/share/functions/help.fish
index dd5480b1d142..9ef1de8c39fc 100644
--- a/share/functions/help.fish
+++ b/share/functions/help.fish
@@ -79,8 +79,7 @@ function help --description 'Show help for the fish shell'
             #
             # We use this instead of xdg-open because that's useless without a backend
             # like wsl-open which we'll check in a minute.
-            if test -f /proc/version
-                and string match -riq 'Microsoft|WSL|MSYS|MINGW' </proc/version
+            if string match -riq 'Microsoft|WSL|MSYS|MINGW' <?/proc/version
                 and set -l cmd (command -s powershell.exe cmd.exe /mnt/c/Windows/System32/cmd.exe)
                 # Use the first of these.
                 set fish_browser $cmd[1]