Merge pull request #238 from summer-wu/master

create tr cheatsheet

cheat/cheatsheets/tr

@@ -0,0 +1,22 @@
+#replace : with new line
+echo $PATH|tr ":" "\n" #equivalent with:
+echo $PATH|tr -t ":" \n 
+
+#remove all occurance of "ab"
+echo aabbcc |tr -d "ab"
+#ouput: cc
+
+#complement "aa"
+echo aabbccd |tr -c "aa" 1
+#output: aa11111 without new line
+#tip: Complement meaning keep aa,all others are replaced with 1
+
+#complement "ab\n"
+echo aabbccd |tr -c "ab\n" 1
+#output: aabb111 with new line
+
+#Preserve all alpha(-c). ":-[:digit:] etc" will be translated to "\n". sequeeze mode.
+echo $PATH|tr -cs "[:alpha:]" "\n" 
+
+#ordered list to unordered list
+echo "1. /usr/bin\n2. /bin" |tr -cs " /[:alpha:]\n" "+"