diff --git a/fish/config.fish b/fish/config.fish
index fbdb74f..1dbc764 100644
--- a/fish/config.fish
+++ b/fish/config.fish
@@ -54,9 +54,6 @@ test -d /usr/sbin       ; and set -x PATH $PATH /usr/sbin
 test -d /sbin           ; and set -x PATH $PATH /sbin
 
 # Aliases
-alias afk='pmset displaysleepnow'
-alias md5sum='md5 -r'
-alias sha256sum='shasum -a 256'
 alias vi='nvim'
 alias vim='nvim'
 
diff --git a/fish/functions/md5sum.fish b/fish/functions/md5sum.fish
new file mode 100644
index 0000000..3b6a34d
--- /dev/null
+++ b/fish/functions/md5sum.fish
@@ -0,0 +1,10 @@
+function md5sum --description 'Compute the MD5 checksum'
+    if command -q md5sum
+        command md5sum $argv
+    else if command -q md5
+        command md5 -r $argv
+    else
+        echo "Command(s) not found: md5sum, md5"
+        return 1
+    end
+end
diff --git a/fish/functions/sha256sum.fish b/fish/functions/sha256sum.fish
new file mode 100644
index 0000000..45cb9e7
--- /dev/null
+++ b/fish/functions/sha256sum.fish
@@ -0,0 +1,10 @@
+function sha256sum --description 'Compute the SHA-256 checksum'
+    if command -q sha256sum
+        command sha256sum $argv
+    else if command -q shasum
+        command shasum -a 256 $argv
+    else
+        echo "Command(s) not found: sha256sum, shasum"
+        return 1
+    end
+end