Text lines head

text-lines-head · version 1.0.0 · Text · free, no key needed

Return the first n parsed lines with LF reconstruction.

Use when you need to: text lines head · first n lines · head lines.

Supported

• text lines head
• first n lines
• head lines

Not supported

• bytes head
• negative n
• follow file

Behavior

• Split on CR LF, LF, or CR. Do not treat other Unicode separators as line breaks.
• A trailing terminator does not create an extra empty line.
• Empty document -> zero lines, trailing_terminator false.
• A document that is only a terminator -> one empty line, trailing_terminator true.
• A document with no terminator -> last line kept, trailing_terminator false.
• Preserve empty lines in the middle.
• Output reconstruction uses LF. If the result has at least one line, append a trailing LF iff the selected window includes the original trailing terminator or includes a line that was followed by a separator in the source.
• No trimming, case folding, Unicode normalization, or locale rules.
• n is a JSON integer, 0 <= n <= max_lines.
• If n is greater than the available line count, return all lines.
• n = 0 yields empty text.

Input

• text (string, required): max length 256000
• n (integer, required): min 0; max 10000

Output

• text (string, required)
• lines_in (integer, required)
• lines_out (integer, required)

Limits

• max input bytes: 256000
• max lines: 10000

Example

Request input:

{
  "text": "a\nb\nc\n",
  "n": 2
}

Response:

{
  "result": {
    "text": "a\nb\n",
    "lines_in": 3,
    "lines_out": 2
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "text-lines-head",
  "version": "1.0.0",
  "input": {
    "text": "a\nb\nc\n",
    "n": 2
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/text-lines-head/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"text":"a\nb\nc\n","n":2}'

The machine-readable contract is at /v1/tools/text-lines-head/versions/1.0.0.

CLI

node cli.mjs run text-lines-head 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Text lines tail: Return the last n parsed lines with LF reconstruction.
• Text count: Count Unicode code points, UTF-16 code units, UTF-8 bytes, and lines.
• Text line diff: Diff two texts as line records, preserving each line terminator.
• Text lines chunk: Split parsed lines into consecutive chunks of size lines each.
• Text lines count: Count exact line multiplicities in first-seen order.
• Text lines difference: Set difference a minus b using exact line equality.