How do I list all the files in a commit?

Question

Preferred Way (because it’s a plumbing command; meant to be programmatic):

$ git diff-tree --no-commit-id --name-only -r bd61ad98
index.html
javascript/application.js
javascript/ie6.js

Another Way (less preferred for scripts, because it’s a porcelain command; meant to be user-facing)

$ git show --pretty="" --name-only bd61ad98    
index.html
javascript/application.js
javascript/ie6.js

The --no-commit-id suppresses the commit ID output.
The --pretty argument specifies an empty format string to avoid the cruft at the beginning.
The --name-only argument shows only the file names that were affected (Thanks Hank). Use --name-status instead, if you want to see what happened to each file (Deleted, Modified, Added)
The -r argument is to recurse into sub-trees