Base64 and echo command

As discussed in a previous post about Kubernetes Secrets data is stored and transmitted in base64 encoded format.
During my own experimentation with this process, I encountered several issues, including problems with unescaped characters, incorrect usernames, and incorrect passwords. I eventually identified the source of these problems and wanted to share the solution in this brief post.

One common method for base64 encoding is using the base64 command-line tool, available on most Linux distributions (and even within Git Bash on Windows). You can convert a value to base64 by issuing the following command:

$ echo "admin" | base64 -w0

However, you’ll likely notice that the output is “YWRtaW4K” and not the expected “YWRtaW4=”. This is because the echo command automatically adds a newline character, which is then included in the base64 encoding process, causing various issues.

The solution is to use the -n flag with the echo command to suppress the newline character. The correct command is:

$ echo -n "admin" | base64 -w0

This will output the correct value. Also for decoding you can easily do that by:

$ echo "YWRtaW4=" | base64 -d

I hope this quick post was useful!