From 31b7a0a6e3e9dd29010004e31e42ca11b9ba1688 Mon Sep 17 00:00:00 2001
From: koalaman <vidar@vidarholen.net>
Date: Mon, 10 Feb 2014 14:30:00 -0800
Subject: [PATCH] Created SC2020 (markdown)

---
 SC2020.md | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 SC2020.md

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+# tr replaces sets of chars, not words (mentioned due to duplicates).
+
+### Problematic code:
+
+    echo 'hello world' | tr 'hello' 'goodbye'
+
+### Correct code:
+
+    echo 'hello world' | sed -e 's/hello/goodbye'
+
+### Rationale:
+
+`tr` is for `tr`ansliteration, turning some characters into other characters. It doesn't match strings or words, only individual characters. 
+
+In this case, it transliterates h->g, e->o, l->d, o->y, resulting in the string "goddb wbrdd" instead of "goodbye world".
+
+The solution is to use a tool that does string search and replace, such as sed. 
+
+### Contraindications
+
+None. 
\ No newline at end of file