I keep forgetting the command to zip a folder in Linux (Red Hat Enterprise Linux 4). And I have even got all files in the folder got zipped individually when I typed the command wrongly, which looked funny to me. The correct command, to remind myself:

zip -9 -r <zip file> <folder name>

To zip a single file:

zip -9 <zip file> <filename>

Use "-9" for best compression. The compressed file works fine with Windows XP compression tool.