split -b —— 方括號表示可以省略的部分。

split

壓縮與傳輸

用法

split -b <size> <file> <prefix>

把大檔案切成好幾塊；預設是按行切、每 1000 行一塊，想按大小切就得寫 `-b 100M`，不給前綴時碎片叫 xaa、xab，拼回去只用一句 `cat part_* > file`，而這能成立全靠後綴本身是有序的。

常用選項

選項	含義
-b 100M	Pieces of a fixed size; K, M and G suffixes work on both platforms.
-l 1000	Split by line count instead, which is the default behaviour at 1000 lines.
-n 4	Cut into exactly four pieces.
-d	Numeric suffixes instead of aa, ab, ac.
-a 3	Suffix length, when two letters are not enough.
--additional-suffix=.part	Append an extension to each piece. GNU only.
<prefix>	Optional, and without it the pieces are named xaa, xab, xac.

範例

split -b 100M big.tar.gz part_

Produces part_aa, part_ab and so on.

cat part_* > big.tar.gz

Reassemble in glob order, which is why the suffixes are sorted.

split -l 5000 -d data.csv chunk_

Five thousand lines per piece, with numeric suffixes.

打包和壓縮是兩件事：tar 打包，gzip 壓小，.tar.gz 是兩樣一起。

怎麼看

Q. split 是做什麼的？

Q. 怎麼寫？

split -b <size> <file> <prefix> —— 方括號表示可以省略的部分。

Q. 值得記的選項有幾個？

這裡列了 7 個，完整列表在 man split。這條命令屬於壓縮與傳輸。