Add nljoin() for joining lines (reverse of nlfor())

dotfiles/bash/main.bashrc

       | fixnl
 }
 
+nljoin() {
+    #
+    # Join lines with $1
+    #
+    # Shorthand for commonly used tr syntax.  Example:
+    #
+    #     $ { echo foo; echo bar; } | nljoin :
+    #
+    # is almost like `tr '\n' :` except that it is a bit easier
+    # to type and fixes the annoying problem with extraneous
+    # newline/colon at the end of final string.
+    #
+    local char=$1
+    tr '\n' "$char" \
+      | sed "s/$char*$//" \
+      | fixnl -c
+}
+
 xop() {
     #
     # Common clipboard operations with fixnl() on top