将CSV文件的前x行读入新的outfile? [英] Read first x lines of csv file into new outfile?

问题描述

如何通过终端仅将csv文件的前x行复制到新的csv文件中?

How would one copy only the first x lines of a csv file into a new csv file via the terminal?

推荐答案

简介

(您将使用linux终端/控制台)

Brief

(You'll use a linux terminal/console)

使用head -n NUMBEROFLINES file.csv来获取第一个NUMBEROFLINES行.像这样使用shell重定向(>)将其写入另一个文件:

Use head -n NUMBEROFLINES file.csv to get the first NUMBEROFLINES of lines. Write it into another file using shell redirection (>) like this:

head -n NUMBEROFLINES file.csv > mynewfile.csv

请注意，这将完全重新创建mynewfile.csv，，如果该内容中有任何内容，则现在将其永久删除(-ish).

Note that this will totally recreate mynewfile.csv, if it had any content before it is now deleted forever(-ish).

如果您碰巧想要相反的内容(最后 x行)，请使用tail.

If you ever happen to want the opposite (last x lines), use tail.

这两个工具都带有手册页和信息页(man head或info head-习惯于man)和--help标志(head --help实际上或多或少显示了手册页).

Both tools come with man and info pages (man head or info head - get used to man, though) and a --help flag (head --help actually shows me more or less the man page).

head -n 10 data.csv >> /tmp/first_and_last.csv # Note the ">>"
tail -n 10 data.csv >> /tmp/first_and_last.csv # Note the ">>"

这将打开文件/tmp/first_and_last.csv，并在/tmp/first_and_last.csv的结尾"处附加(>>，>将重新创建/删除文件！)data.csv的前10行.

This would open the file /tmp/first_and_last.csv and attach (>>, > would recreate/delete the file!) the first and the last 10 lines of data.csv at the "end" of /tmp/first_and_last.csv.

Mac OS: 根据Internet(tm)，这些命令在基于Mac的Mac OS中也可用(您必须通过Finder启动终端).

Mac OS: According to the internet (tm) these commands are available in (Unix-based) Mac OS as well (you have to start the Terminal via Finder).

更多口语示例

-n是--lines=的缩写，因此您也可以使用:

-n is short for --lines=, so you could also use:

tail --lines=10 data.csv >> addtothisfile.txt
head --lines=10 data.csv >> addtothisfile.txt

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