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GitHub - lenik/strsplit: Split input strings by delimiter and print each item on separate line

Split input string(s) by delimiter and print each item as a separate line.

Synopsis

strsplit [OPTIONS] ARGS...

If ARGS are provided, each argument is treated as one input line (one run).

If no argument is specified, input is read from stdin, line by line (each line is one run).

Description

For each run:

  1. Take input string
  2. Optionally case-fold
  3. Split by delimiter (default: whitespace \s+)
  4. Optionally sort
  5. Print items according to format rules

A run is defined as:

  • One command-line argument, OR
  • One line read from stdin

Installation

Building from Source

# Install build dependencies
sudo apt install meson ninja-build gcc

# Configure and build
meson setup builddir
cd builddir
ninja

# Install (optional)
sudo ninja install

Debian Package

# Build Debian package
dpkg-buildpackage -us -uc

# Install the package
sudo dpkg -i ../strsplit_*.deb

Options

Delimiter

Use POSIX Extended Regular Expression as delimiter.
Default: \s+

Delimiter matches are not included in output.

Line Numbering

Print line number before each split item.

Default numbering base: 1

Use 0-based numbering.

Reset numbering between runs.

Default behavior:

  • If multiple runs and -z not specified → numbering continues across runs
  • If -z specified → numbering restarts per run

Output Formatting

Custom output format.

If -n is enabled:

  • Default format: "%d. %s"

If -n is not enabled:

  • Default format: "%s"

Format placeholders:

Placeholder Meaning
%d item index
%s item string

Undefined placeholders → implementation-defined (may pass to printf).

Run Separation

Insert one blank line between runs.

May be specified repeatedly:

  • -N → 1 blank line
  • -NN → 2 blank lines
  • etc.

No trailing blank lines after last run.

Indentation

Indent output by 2 spaces per level.

Repeatable:

  • -i → 2 spaces
  • -ii → 4 spaces

Indentation applies to each output line.

Sorting

Sorting applies after splitting and before printing.

Reverse final ordering.

Sort Modes (mutually exclusive)

-f, --ignore-case
    Case-insensitive lexicographic sort

-s, --numeric-sort
    Compare using strtol()

-g, --general-numeric-sort
    Compare using strtod()

-H, --human-numeric-sort
    Human numeric (e.g. 2K < 10K)

-D, --dictionary-sort
    Compare ignoring non-alphanumeric chars

-V, --version-sort
    Version-aware sort (e.g. 1.9 < 1.10)

If multiple sort modes specified → last one wins.

If no sort option specified → preserve original order.

Processing Order

For each run:

  1. Read input
  2. If -f specified → fold case (implementation: toupper())
  3. Split using delimiter regex
  4. Preserve empty items (if delimiter produces empty tokens)
  5. Apply selected sort (if any)
  6. Apply reverse (if -r)
  7. Output with formatting
  8. Insert run-separator newlines (if -N and not last run)

Exit Status

Code Meaning
0 success
1 invalid arguments
2 runtime error

Examples

Basic split

Output:

With numbering (0-based) and reset

strsplit -z0niN 'foo bar' 'cat dog'

Output:

  0. foo
  1. bar

  0. cat
  1. dog

Numeric sort

Output:

Version sort

strsplit -V "1.2 1.10 1.3"

Output:

Custom delimiter

strsplit -d "," "foo,bar,baz"

Output:

Read from stdin

echo "foo bar baz" | strsplit

Output:

Edge Cases

  • Empty input line → no output
  • Delimiter matching entire string → no output
  • Large input → dynamic realloc growth
  • UTF-8 handling → byte-wise unless extended

Bash Completion

Source the completion script or install it to your bash completion directory:

source bash-completion/strsplit

Or copy to system completion directory:

sudo cp bash-completion/strsplit /etc/bash_completion.d/

License

Copyright (C) 2026 Lenik strsplit@bodz.net

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

Author

Lenik strsplit@bodz.net

Bug Reports

Please report bugs and feature requests at: https://github.com/lenik/strsplit/issues