diff --git a/.version b/.version
index cd5ac03..879b416 100644
--- a/.version
+++ b/.version
@@ -1 +1 @@
-2.0
+2.1
diff --git a/README.md b/README.md
index b1c426c..03d5783 100644
--- a/README.md
+++ b/README.md
@@ -346,4 +346,5 @@ Adam,Monika,Slawek,Daniel,Bartek
 
 
 # Resources
-* [Inspiration](https://quasimal.com/posts/2012-05-21-funsh.html)
\ No newline at end of file
+* [Inspiration](https://quasimal.com/posts/2012-05-21-funsh.html)
+* [Functional Programming in Bash](https://medium.com/@joydeepubuntu/functional-programming-in-bash-145b6db336b7)
\ No newline at end of file
diff --git a/src/fun.sh b/src/fun.sh
index 9608852..d0b3af8 100755
--- a/src/fun.sh
+++ b/src/fun.sh
@@ -193,6 +193,26 @@ filter() {
   done
 }
 
+pass() {
+  echo > /dev/null
+}
+
+dropw() {
+  local x
+  while read x && $(echo "$x" | "$@"); do
+    pass
+  done
+  [[ ! -z $x ]] && { echo $x; cat -; }
+}
+
+peek() {
+  local x
+  while read x; do
+    ([ $# -eq 0 ] && 1>&2 echo $x || 1>&2 "$@" < <(echo $x))
+    echo $x
+  done
+}
+
 stripl() {
   local arg=$1
   cat - | map lambda l . 'ret ${l##'$arg'}'