diff --git a/SC2012.md b/SC2012.md
index 4a7e188..6d07ab9 100644
--- a/SC2012.md
+++ b/SC2012.md
@@ -1,17 +1,99 @@
-# Use find instead of ls to better handle non-alphanumeric filenames.
+## Use `find` instead of `ls` to better handle non-alphanumeric filenames.
 
-## Problematic code:
+### Problematic code:
 
-TODO
+```sh
+ls -l | grep " $USER " | grep '\.txt$'
+```
+```sh
+NUMGZ="$(ls -l *.gz | wc -l)"
+```
 
-## Correct code:
+### Correct code:
 
-TODO
+```sh
+find . -maxdepth 1 -name '*.txt' -user "$USER"  # Using the names of the files
+```
+```sh
+gz_files=(*.gz)
+numgz=${#gz_files[@]} # Sometimes, you just need a count
+````
+### Rationale:
 
-## Rationale
+`ls` is only intended for human consumption: it has a loose, non-standard format and may "clean up" filenames to make output easier to read.
 
-TODO
+Here's an example:
 
-### Exceptions
+```sh
+$ ls -l
+total 0
+-rw-r----- 1 me me 0 Feb  5 20:11 foo?bar
+-rw-r----- 1 me me 0 Feb  5  2011 foo?bar
+-rw-r----- 1 me me 0 Feb  5 20:11 foo?bar
+```
 
-TODO
+It shows three seemingly identical filenames, and did you spot the time format change? How it formats and what it redacts can differ between locale settings, `ls` version, and whether output is a tty.
+
+### Tips for replacing `ls` with `find`:
+
+#### Just the filenames, ma'am
+
+`ls` can usually be replaced by `find` if it's just the filenames, or a count of them, that you're after. Note that if you are using `ls` to get at the contents of a directory, a straight substitution of `find` may not yield the same results as `ls`. Here is an example:
+
+```
+$ ls -c1 .snapshot
+rnapdev1-svm_4_05am_6every4hours.2019-04-01_1605
+rnapdev1-svm_4_05am_6every4hours.2019-04-01_2005
+rnapdev1-svm_4_05am_6every4hours.2019-04-02_0005
+rnapdev1-svm_4_05am_6every4hours.2019-04-02_0405
+rnapdev1-svm_4_05am_6every4hours.2019-04-02_0805
+rnapdev1-svm_4_05am_6every4hours.2019-04-02_1205
+snapmirror.1501b4aa-3f82-11e8-9c31-00a098cef13d_2147868328.2019-04-01_190000
+```
+versus
+```
+$ find .snapshot -maxdepth 1
+.snapshot
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0005
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0405
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0805
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-01_1605
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-01_2005
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_1205
+.snapshot/snapmirror.1501b4aa-3f82-11e8-9c31-00a098cef13d_2147868328.2019-04-01_190000
+```
+You can see two differences here. The first is that the `find` output has the full paths to the found files, relative to the current working directory from which `find` was run whereas `ls` only has the filenames. You may have to adjust your code to not add the directory to the filenames as you process them when moving from `ls` to `find`, or (with GNU find) use `-printf '%P\n'` to print just the filename.
+
+The second difference in the two outputs is that the `find` command includes the searched directory as an entry. This can be eliminated by also using `-mindepth 1` to skip printing the root path, or using a negative name option for the searched directory:
+```
+$ find .snapshot -maxdepth 1 ! -name .snapshot
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0005
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0405
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0805
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-01_1605
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-01_2005
+.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_1205
+.snapshot/snapmirror.1501b4aa-3f82-11e8-9c31-00a098cef13d_2147868328.2019-04-01_190000
+```
+
+**Note:** If the directory argument to `find` is a fully expressed path (`/home/somedir/.snapshot`), then you should use `basename` on the `-name` filter:
+
+```
+$ theDir="$HOME/.snapshot"
+$ find "$theDir" -maxdepth 1 ! -name "$(basename $theDir)"
+/home/matt/.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0005
+/home/matt/.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0405
+/home/matt/.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_0805
+/home/matt/.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-01_1605
+/home/matt/.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-01_2005
+/home/matt/.snapshot/rnapdev1-svm_4_05am_6every4hours.2019-04-02_1205
+/home/matt/.snapshot/snapmirror.1501b4aa-3f82-11e8-9c31-00a098cef13d_2147868328.2019-04-01_190000
+```
+
+#### All the other info
+
+If trying to parse out any other fields, first see whether `stat` (GNU, OS X, FreeBSD) or `find -printf` (GNU) can give you the data you want directly.
+
+### Exceptions:
+
+If the information is intended for the user and not for processing (`ls -l ~/dir | nl; echo "Ok to delete these files?"`) you can ignore this error with a [[directive]].