key points:
cp [old] [new]
copies a file.mkdir [path]
creates a new directory.mv [old] [new]
moves (renames) a file or directory.rm [path]
removes (deletes) a file.*
matches zero or more characters in a filename, so *.txt
matches all files ending in .txt
.?
matches any single character in a filename, so ?.txt
matches a.txt
but not any.txt
.something.extension
. The extension isn’t required, and doesn’t guarantee anything, but is normally used to indicate the type of data in the file.