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Environment Variable Reference Name Inventory

Inventory literal $NAME or ${NAME} reference syntax with UTF-16 spans; no shell quoting, escapes, operators or double-dollar PID semantics are interpreted.

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Description

Inventory literal $NAME or ${NAME} reference syntax with UTF-16 spans; no shell quoting, escapes, operators or double-dollar PID semantics are interpreted.

Environment assignments pair names with literal string values. Repeated names need an explicit first/last policy, and missing values differ from present empty strings. A dotenv file and a shell program can use different quoting and expansion rules; these tools implement their stated literal subsets using supplied data.

Inventory literal $NAME or ${NAME} reference syntax with UTF-16 spans; no shell quoting, escapes, operators or double-dollar PID semantics are interpreted.

When to use this tool

Use this tool to inventory literal $NAME or ${NAME} reference syntax with UTF-16 spans; no shell quoting, escapes, operators or double-dollar PID semantics are interpreted.

How to use the tool and how it works

  1. Enter text using the input definitions below.
  2. Run the operation. Resolve malformed-input errors before interpreting the result.
  3. Read result.references. Interpret signs, units, ordering and null values using the rules below.

Scan left to right for $NAME or ${NAME}, with NAME matching [A-Za-z_][A-Za-z0-9_]*, and return name plus half-open UTF-16 source spans.1

Input fieldMeaning and unitsAccepted input
textLiteral text to scan for the stated simple dollar-reference syntax.Text, at most 8,192 UTF-16 code units; the stated grammar and narrower limits also apply.
Output fieldInterpretation
resultObject containing the fields below.
result.referencesOriginal simple reference names with half-open UTF-16 source spans.
json
{
  "input": {
    "text": "$A ${B} $$A"
  },
  "output": {
    "result": {
      "references": [
        {
          "name": "A",
          "start": 0,
          "end": 2
        },
        {
          "name": "B",
          "start": 3,
          "end": 7
        },
        {
          "name": "A",
          "start": 9,
          "end": 11
        }
      ]
    }
  }
}

Limitations and assumptions

  • The scan ignores shell quote/escape rules and PID syntax: in $$A, the second dollar begins a literal $A reference.
  • Portable assignment records require names matching [A-Za-z_][A-Za-z0-9_]* and NUL-free values. Name matching is case-sensitive. Reference scanners and quoted-value helpers follow only their own stated grammar and do not read the process environment.
  • Every declared top-level input is required and unknown fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
  • Numeric outputs must be finite and within the absolute safe-integer magnitude; exact larger integers use decimal text. Source positions are zero-based UTF-16 offsets and span ends are exclusive unless a different convention is explicitly stated.

Alternative or Complementary methods

Select the consuming application’s dotenv dialect explicitly. Keep literal substitution separate from recursive expansion and shell execution, and retain occurrence provenance when resolving duplicate assignments.

References

  1. Tool behavior and example: Environment Variable Reference Name Inventory — tool.io

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