Command Line
How to Use rev and tac and Other Text Reversers Step by Step
Reverse characters with rev and lines with tac, plus last field extraction, reverse sort, and the portable alternatives for macOS where tac is missing.
6 min read
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6 posts
Text Processing
How to Remove Duplicate Lines From a File Without Sorting
Remove duplicate lines from a file while keeping the original order: the awk '!seen[$0]++' idiom, deduplicating by field, case-insensitively and in place.
6 min read
Command Line
How to Use fold fmt and nl to Format Text Without Surprises
Use fold, fmt and nl to wrap lines, reflow paragraphs and number text from the terminal, and know which one breaks words, which respects them, and why.
6 min read
Regular Expressions
Regex vs String Functions for Simple Text Tasks Explained
Decide between regex and string functions for simple text tasks: prefix, suffix, contains, split and replace, with readability, speed and safety.
6 min read
Text Processing
How to Split a File by Lines Size or Pattern With Examples
Split a file by line count, size or pattern with split and csplit, name the pieces, keep headers, and split compressed streams without temporary files.
6 min read
Text Processing
How to Compare Two Files and Show Only Differences
Compare two files and show only the differences with diff, cmp, comm and git diff, in unified, side-by-side and word-level views, and ignore whitespace.
6 min read