csplit

Additional Notes

csplit splits a file into pieces based on line numbers or matching patterns. It is useful for breaking structured text into separate files.

Use it when simple byte or line counts from split are not enough.

Syntax

csplit [options] file pattern...

Parameters

• file: Input file to split.
• pattern: Line number, regular expression, or repeat expression that defines split points.
• options: Output prefix, suffix, quiet, and keep controls.

Common Options

• -f PREFIX: Use PREFIX for output files.
• -b FORMAT: Use FORMAT for output suffixes.
• -n DIGITS: Use DIGITS in output numbering.
• -k: Keep output files on errors.
• -s: Silent mode.
• -z: Remove empty output files.

Examples

csplit document.txt 100

Split before line 100.

csplit -f part- document.txt '/^Chapter/' '{*}'

Split at each line beginning with Chapter.

csplit -z -f section- input.txt '/^---$/' '{*}'

Split on separator lines and remove empty files.

Practical Notes

• Patterns are evaluated in order.
• Quote regex patterns so the shell does not interpret them.
• Use split for fixed-size splitting and csplit for content-aware splitting.