Data Formats for Admins: JSON, YAML, XML, TOML

This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.

What this hour is for

JSON is strict and has no comments. YAML cares about indentation. XML is tagged and verbose. TOML and INI suit many config files. The formatters and converters run in the browser on text you paste. They do not write a server.

Use the format the program already reads. Converting the only copy of a production file is how you lose it. Convert a copy. Remove secrets before you paste.

example.com and a sample password do not belong in the file you save. 192.0.2.10/24 and example.com are documentation. They stay in the note.

The change you can finish

Apply nothing while you are writing the note. When the lab window opens, it is one change on the host named in the ticket. Read the draft, then the host, then decide.

Rollback is the file, the package version, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.

Name the program and the format it reads.
Paste a copy with secrets removed.
Format or convert that copy.
Do not replace the only original.
Stop.

Mistakes that outlive the command

Data Formats for Admins: JSON, YAML, XML, TOML goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.

A secret pasted into the tool.
The only copy converted in place.
A format the program does not read.
Indentation ignored in YAML.

Decisions to write down

One decision for Data Formats for Admins: JSON, YAML, XML, TOML: The format matches the program. The original is intact. Secrets were removed first. The conversion is a copy. And the tools did not write a server.

Checks before you call it done

Confirm this before you call the change done: The program is named. The format is named. The original path is untouched. No secret is in the paste. And the result is a copy. If one of those fails, stop.

Format	Watch	Usual place
JSON	No comments	APIs and many tools
YAML	Indentation	Kubernetes, Ansible, netplan
XML	Tags	Older enterprise config
TOML or INI	Simple keys	Application config

# Convert a copy.
# Remove secrets first.
# Use the format the program already reads.

Before you leave the host

Data Formats for Admins: JSON, YAML, XML, TOML ends when the hostname in the prompt matches the hostname in the ticket. If it does not, you are on the wrong host. Stop. A command that succeeded on the wrong host is not progress.

The draft stays a draft until a person has read the names in it. A generator does not log into the host and does not know which disk is empty. You delete a line that names a host, a path, or an account you did not write down.

192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a host because a draft included them.

prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save in the ticket or in git. The real secret stays in the password store.

One change is the window. If two things move and the result is wrong, you will not know which one did it. The next change waits for its own page.

If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied change produces a host nobody can rebuild. Restore the copy you took first.

A second person reads the hostname and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the host alone.

This page is a planning guide. It is not a vendor manual, not an official standard, and not permission to touch a host you do not administer. You do not disable a firewall, AppArmor, or SELinux to make a check pass.

Tools for this guide

These tools run in the browser on this site. They do not log into your machines.

Everyday Utilities for Sysadmins

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