Command-line TSV viewer

tsvless.py

#!/usr/bin/env python3
"""View a tsv in less with suitable tabstops"""
import itertools
from pathlib import Path
import os


def tabline(tsv: Path) -> str:
    """Compute a suitable tabline for `less --tabs`"""
    max_widths = []
    for line in tsv.open():
        widths = [len(cell) for cell in line.split("\t")]
        if len(widths) > len(max_widths):
            max_widths.extend([0] * (len(widths) - len(max_widths)))
        for i, w in enumerate(widths):
            max_widths[i] = max(max_widths[i], w)
    tab_stops = itertools.accumulate(w + 2 for w in max_widths)
    return ",".join(map(str, tab_stops))


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("tsv", type=Path)
    args = parser.parse_args()

    os.execlp(
        "less",
        "less",
        "--tabs",
        tabline(args.tsv),
        "--chop-long-lines",
        "--",
        str(args.tsv),
    )