Extracting *.csv from a hundred zips and appending results

Question

What would be an efficient way to extract only all of the *.csv files (not other files inside) from inside a hundred zip files in a single directory? Then I need to make one large file with each CVS file appended together although stripping off header line 1 from files 2,...,n.

If it works well I would like to use 7-Zip's 7za.exe the command line version or other solutions that are self contained and don't require installation on a WinXP platform. The zips contain other data I don't need.

Simple appending is easy with file1+file2+..., but how about dropping the header?

Answer 1

Actually, to skip the header in Unix/Linux, you would need the 'tail' command.

You can tell the 'tail' command to skip the first line (the header) by doing the following:

tail -n+2 filename

This will tell tail to start reading from line 2.

To do this on all .csv files in your current directory, and append them together, put the following in a script:

#!/bin/bash

for file in *.csv
do
tail -n+2 $file
done

You can then run this script like ./script.sh>output and the output will be in the file named 'output'.

Unfortunately I do not know if something like tail is available in any capacity on Windows without ports.

Answer 2

but how about dropping the header?

With the unix 'head' command (from mingw, opench or a bunch of other utils) you can use "head -n" to show all but the first 'n' lines

Answer 3

To my embarrassment the answer on extracting just a particular file type from within a all compressed files in a directory with 7Zip is simply:

7za.exe e *.zip *.csv

Then to combine the files with a batch file (although its disappointing this single line can't be typed in to the command prompt)

[saved as foo.bat for example]
for %%X in (*.csv) do tail -n+2 %%X >> combined.csv