# split — Break Files into Smaller Pieces > Practical guide to split — break large files into pieces by line count, byte size or number of chunks. Useful for processing, transfer and parallel jobs. Source: https://www.jpkc.com/db/en/cheatsheets/files-text/split/ split breaks a file into several smaller pieces – by line count (`-l`), byte size (`-b`) or a fixed number of chunks (`-n`). That is handy for making huge log files manageable, chopping large archives for transfer, or splitting data for parallel processing. By default the pieces get an alphabetic suffix (`xaa`, `xab`, …), which you can tailor with a custom prefix as well as numeric suffixes and extensions. You reassemble the pieces with a simple `cat`, as long as you preserve their order. ## Split by Lines `split -l ` — Split file into pieces of n lines each. ```bash split -l 1000 largefile.txt ``` `split -l ` — Split with a custom output prefix. ```bash split -l 500 data.csv part_ ``` `split -l 1 ` — Split each line into its own file. ```bash split -l 1 urls.txt url_ ``` ## Split by Size `split -b ` — Split into pieces of specified byte size (K, M, G suffixes). ```bash split -b 10M largefile.tar.gz chunk_ ``` `split -C ` — Split at line boundaries, keeping pieces under the size limit. ```bash split -C 1M logfile.txt log_ ``` `split -b 100K ` — Split into 100KB chunks with a custom prefix. ```bash split -b 100K backup.sql sql_ ``` ## Split by Count `split -n ` — Split into exactly n files of roughly equal size. ```bash split -n 5 largefile.txt part_ ``` `split -n l/ ` — Split into n files without breaking lines. ```bash split -n l/4 data.csv quarter_ ``` `split -n r/ ` — Distribute lines round-robin across n files. ```bash split -n r/3 tasks.txt worker_ ``` ## Output Options `split -d ` — Use numeric suffixes (00, 01, 02...) instead of alphabetic (aa, ab, ac...). ```bash split -d -l 1000 data.csv part_ ``` `split -a ` — Set the suffix length (default is 2). ```bash split -a 4 -l 100 huge.txt piece_ ``` `split --additional-suffix='.txt' ` — Add a file extension to output files. ```bash split -l 500 --additional-suffix='.csv' data.csv part_ ``` `split --verbose ` — Print a message for each output file created. ```bash split --verbose -l 1000 data.txt chunk_ ``` `split --filter='' ` — Pipe each piece through a command instead of writing to files. ```bash split -l 1000 --filter='gzip > $FILE.gz' data.txt part_ ``` ## Common Patterns `split -b 25M file.tar.gz part_ && cat part_* > file.tar.gz` — Split a large file for transfer, then reassemble. ```bash split -b 25M backup.tar.gz upload_ && cat upload_* > backup_restored.tar.gz ``` `split -l 1000 data.csv batch_ && for f in batch_*; do process "$f"; done` — Split data and process each batch. ```bash split -l 1000 users.csv batch_ && for f in batch_*; do ./import.sh "$f"; done ``` `wc -l && split -n l/ ` — Check line count, then split evenly for parallel processing. ```bash wc -l data.csv && split -n l/$(nproc) data.csv worker_ ``` ## Conclusion split is the go-to when a file is too big for a tool, an upload or a chunk of memory. Remember the difference between the modes: `-b` cuts strictly by bytes (and may break mid-line), `-C` and `-n l/…` respect line boundaries, and `-n r/…` distributes round-robin. Reassembly comes down to order alone – `cat prefix_*` works because the shell sorts the alphabetic suffixes correctly; so allow enough suffix digits (`-a`) for the sort to hold even with many pieces. After reassembling large binary files, it is wise to verify the checksum. ## Further Reading - [GNU coreutils: split](https://www.gnu.org/software/coreutils/manual/html_node/split-invocation.html) – official reference with all options - [split(1) man page](https://man7.org/linux/man-pages/man1/split.1.html) – the Linux manual page for split ## Related Commands - [cut](https://www.jpkc.com/db/en/cheatsheets/files-text/cut/) – extract fields, characters or byte ranges from lines - [head](https://www.jpkc.com/db/en/cheatsheets/files-text/head/) – show the first lines or bytes of a file - [tail](https://www.jpkc.com/db/en/cheatsheets/files-text/tail/) – show the last lines of a file or follow it live