bin: adjust pbcopy/pbpaste for BSD/Linux/mac

bin/pbcopy_l

@@ -1,5 +1,9 @@
 #!/bin/sh
-if [ "$(uname)" != "Linux" ] ; then
-    /usr/bin/pbcopy $*
+OS=$(uname)
+if [ "$OS" == "Linux" -o "$OS" == "FreeBSD" ] ; then
+  xsel -i -b
+elif [ "$(uname)" == "Darwin" ] ; then
+  /usr/bin/pbcopy $*
+else
+  echo "Unknown OS."
 fi
-xsel -i -b

bin/pbpaste_l

@@ -1,5 +1,9 @@
 #!/bin/sh
-if [ "$(uname)" != "Linux" ] ; then
-    /usr/bin/pbpaste $*
+OS=$(uname)
+if [ "$OS" == "Linux" -o "$OS" == "FreeBSD" ] ; then
+  xsel -o -b
+elif [ "$(uname)" == "Darwin" ] ; then
+  /usr/bin/pbpaste $*
+else
+  echo "Unknown OS."
 fi
-xsel -o -b