Dockerfile ENV Instruction in PY
Match Dockerfile `ENV KEY=value` (or `ENV KEY value`) instructions, capturing key and value.
Try it in the PY tester →Pattern
regexPY
^ENV\s+([A-Z_][A-Z0-9_]*)(?:[=\s]+)(.+)$ (flags: gm)Python (re) code
pyPython
import re
pattern = re.compile(r"^ENV\s+([A-Z_][A-Z0-9_]*)(?:[=\s]+)(.+)$", re.MULTILINE)
input_text = "ENV NODE_VERSION=20.10.0\nENV PORT 3000"
for m in pattern.finditer(input_text):
print(m.group(0))Stdlib `re` module — no third-party dependency. Works on Python 3.6+.
How the pattern works
^ENV anchors to the line start (m flag enables per-line). \s+ requires whitespace. ([A-Z_][A-Z0-9_]*) captures the key (uppercase + underscores by convention). [=\s]+ matches either the modern `=` separator or the legacy whitespace separator. (.+)$ captures the rest of the line as the value.
Examples
Input
ENV NODE_VERSION=20.10.0\nENV PORT 3000Matches
ENV NODE_VERSION=20.10.0ENV PORT 3000
Input
ENV DATABASE_URL=postgres://localhost/dbMatches
ENV DATABASE_URL=postgres://localhost/db
Input
FROM node:20No match
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