Add extract function for fish

fish/.config/fish/functions/extract.fish

@@ -0,0 +1,23 @@
+function extract --description "Expand or extract bundled & compressed files"
+  set --local ext (echo $argv[1] | awk -F. '{print $NF}')
+  switch $ext
+    case tar  # non-compressed, just bundled
+      tar -xvf $argv[1]
+    case gz
+      if test (echo $argv[1] | awk -F. '{print $(NF-1)}') = tar  # tar bundle compressed with gzip
+        tar -zxvf $argv[1]
+      else  # single gzip
+        gunzip $argv[1]
+      end
+    case tgz  # same as tar.gz
+      tar -zxvf $argv[1]
+    case bz2  # tar compressed with bzip2
+      tar -jxvf $argv[1]
+    case rar
+      unrar x $argv[1]
+    case zip
+      unzip $argv[1]
+    case '*'
+      echo "unknown extension"
+  end
+end