slice

Slice rows by index (keep or drop).

Behavior:

• Selects specific rows by 1-based index (Keep Mode) or excludes them (Drop Mode).
• Row indices refer to absolute line numbers (including header lines when header mode is enabled).
• Range syntax:
  • N - Single row (e.g., 5).
  • N-M - Row range from N to M (e.g., 10-20).
  • N- - From row N to end of file (e.g., 10-).
  • -M - From row 1 to row M (e.g., -5 is equivalent to 1-5).
• Multiple ranges can be specified with multiple -r/--rows flags.
• Use --invert to drop selected rows instead of keeping them.

Input:

• Reads from files or standard input.
• Files ending in .gz are transparently decompressed.

Output:

• By default, output is written to standard output.
• Use --outfile to write to a file instead.

Header behavior:

• Supports all four header modes. See tva --help-headers for details.
• When header is enabled, header lines are preserved in the output.

Examples:

1. Keep rows 10 to 20 tva slice -r 10-20 file.tsv

2. Keep first 5 rows tva slice -r -5 file.tsv

3. Drop row 5 (exclude it) tva slice -r 5 --invert file.tsv

4. Preview with header (keep rows 100-110 plus header) tva slice -H -r 100-110 file.tsv