Concatenate table without header

Question

I would like to concatenate several tables and just keeping the header in the first line (and thus not having a new header each time that a new table has been concatenate). Does anyone know how to do that?

I am currently using:

find "/dir/folder" name "*.dat" -exec cat {} + >> "/dir/folder/table.txt"

but I can get rid of the header with that.

Answer 1

With a BSD/GNU sed:

find "/dir/folder" -name "*.dat" -exec sed -se1d {} + >> "/dir/folder/table.txt"

...which instructs to treat all input files separately, and for each to delete the 1st line.

If the header isn't already in table.txt, you should first put it there, though:

set -- /dir/folder/*.dat
head -n1 <"$1" >>/dir/folder/table.txt
find ...

If all of the *.dat matches are in child directories, that won't work though.

{   find /dir/folder -name \*.dat -exec \
         sh -c 'head -n1 "$0"; kill "$PPID"' {} \;
    find /dir/folder -name \*.dat -exec sed -se1d {} +
}   >>/dir/folder/table.txt

That should.

Answer 2

If the header is on one line, with GNU tail:

find "/dir/folder" -name "*.dat" -exec tail -qn +2 {} +

POSIXly, you'd need to run one tail per file:

To preserve the header of the first file, GNUly:

find "/dir/folder" -name "*.dat" -print0 | {
   IFS= read -rd '' first &&
     cat "$first" &&
     xargs -r0 tail -qn +2
}

Answer 3

If all your files can be fit in to one awk invocation:

find "/dir/folder" name "*.dat" -exec awk 'FNR == 1 && NR != 1 {next};1' {} + 

Answer 4

tail allow you to skip given number of lines:

find "/dir/folder" name "*.dat" -exec tail +2 {} + >> "/dir/folder/table.txt"