This is a follow up to the previous post on things that trip newbies in Powershell

In this post, I will be concentrating on Encodings. When I began using Powershell, it managed to confuse, trick and irritate me a lot. Encodings issues continue to be problematic with Powershell even in v3.0.

Let me start off with a common enough usage that might come to bite you. Say you have a git repo. You can want to pipe some content to .gitignore to ignore some files and directories. Easy right?

You can do:

"*.dll" > .gitignore

As any git user would know, that should ignore any dll file in your repo. But will it? Go ahead try it out.

PS> git init .
PS> touch a.dll
PS> "*.dll" > .gitignore
PS> git add .
PS> git status
# On branch master
# Initial commit
# Changes to be committed:
#   (use "git rm --cached <file>..." to unstage)
#       new file:   .gitignore
#       new file:   a.dll

What??? Shouldn’t a.dll be ignored. Let’s see what’s going on here:

PS> git diff --cached
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2f14638
Binary files /dev/null and b/.gitignore differ
diff --git a/a.dll b/a.dll
new file mode 100644
index 0000000..e69de29

So git is treating the .gitignore file as a binary. This is where encodings come into the picture.

Doing "*.dll" > .gitignore is pretty much the same as doing "*.dll" | out-file .gitignore. The default encoding that is used here is UCS-2. Many tools like git are not happy with it, at least by default.

We have this, from the docs:

By default, the Out-File cmdlet creates a Unicode file. This is the best default in the long run, but it means that tools that expect ASCII files will not work correctly with the default output format. You can change the default output format to ASCII by using the Encoding parameter

To make git happy, you can convert the .gitignore file to, say ascii. Actually, the out-file cmdlet provides ability to do just that.

 "*.dll" | out-file -Encoding ascii .gitignore

Now, the dlls should be ignored as expected. Unfortunately, there is no way to change how > behaves in this aspect!