Pulling a subset of data from a larger data set

[blairb]

Hi,

I've got a file that's ~8,500 lines long and I want to pull out a subset of ~1,500 of these lines. Each line is a specific sample and I have a list of samples that I want to pull from this main data file. Just wondering which command would be best to implement this.

Regards,
Blair

[Banfa]

So assuming that you have the unique ids of the 1500 samples you want in a file (ids) and the data is in a file (samples) and that final order of retrieved samples is not important you could do something like this

cat ids | xargs -I '{}' grep '{}' samples

[blairb]

Many thanks for the response, it's much appreciated.

My coding is far from advanced, so just to clarify - do I need to put any parameters in the '{}' field?
i.e. I've got a file with the samples I want (ids.csv) and the data file (samples.xls) so my code would simply be

cat ids.csv | xargs -I '{}' grep '{}' samples.xls > catdata.xls

Is this correct?

[Banfa]

The command line looks about right. Nothing needs placing in the '{}' field, read the man pages for xargs (man xargs) the -I switch specifies a string that should be replaced with the names read in from standard in (that is the output of the cat command in this case).

However I am concerned that you appear to be trying to work on xls (Excel) files as though they text files which they are not (unless they happen to contain csv data in which case why not use the csv extension). You may be able to achieve what you want by exporting the xls to a csv first though.