Created SC1017 (markdown)

SC1017.md

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+## Literal carriage return. Run script through `tr -d '\r'` .
+
+### Problematic code:
+
+```sh
+$ cat -v myscript
+#!/bin/sh^M
+echo "Hello World"^M
+```
+
+### Correct code:
+
+```sh
+$ cat -v myscript
+#!/bin/sh
+echo "Hello World"
+```
+### Rationale:
+
+The script uses Windows/DOS style `\r\n` line terminators instead of UNIX style `\n` terminators. The additional `\r` aka `^M` aka carriage return characters will be treated literally, and results in all sorts strange bugs and messages.
+
+You can verify this with `cat -v yourfile` and see whether or not each line ends with a `^M`. To delete them, open the file in your editor and save the file as "Unix", "UNIX/OSX Format", `:set ff=unix` or similar if it supports it.
+
+If you don't know how to get your editor to save a file with Unix line terminators, you can use `tr`:
+
+    tr -d '\r' < badscript   > goodscript
+
+This will read a script `badscript` with possible carriage returns, and write `goodscript` without them.
+
+### Exceptions:
+
+None