bash - Make cat command to operate recursively looping through a directory -

i have large directory of data files in process of manipulating them in desired format. each begin , end 15 lines soon, meaning need strip first 15 lines off 1 file , paste them end of previous file in sequence.

to begin, have written following code separate relevant data easy chunks:

#!/bin/bash  destination='media/user/directory/' file1 in `ls $destination*.ascii`     echo $file1     file2="${file1}.end"     file3="${file1}.snip"     sed -e '16,$d' $file1 > $file2     sed -e '1,15d' $file1 > $file3 done 

this worked perfectly, next step worlds simplest cat command:

cat $file3 $file2 > outfile 

however, need stitch file2 previous file3. look @ screenshot of directory better understanding.

see how these files sequential on time:

*_20090412t235945_20090413t235944_*    ### april 13 *_20090413t235945_20090414t235944_*    ### april 14 

so need take 15 lines snipped off april 14 example above , paste end of april 13 example.

this doesn't have part of original code, in fact best if weren't. hoping able me going.

thanks in advance! if there have been unclear , needs further explanation please let me know.

"i need strip first 15 lines off 1 file , paste them end of previous file in sequence."

if understand want correctly, can done 1 line of code:

awk 'nr==1 || fnr==16{close(f); f=filename ".new"} {print>f}' file1 file2 file3 

when has run, files file1.new, file2.new, , file3.new in new form lines transferred. of course, not limited 3 files: may specify many on command line.

example

to keep our example short, let's strip first 2 lines instead of 15. consider these test files:

$ cat file1 1 2 3 $ cat file2 4 5 6 7 8 $ cat file3 9 10 11 12 13 14 15 

here result of running our command:

$ awk 'nr==1 || fnr==3{close(f); f=filename ".new"} {print>f}' file1 file2 file3 $ cat file1.new 1 2 3 4 5 $ cat file2.new 6 7 8 9 10 $ cat file3.new 11 12 13 14 15 

as can see, first 2 lines of each file have been transferred preceding file.

how works

awk implicitly reads each file line-by-line. job of our code choose new file line should written based on line number. variable f contain name of file writing to.

• nr==1 || fnr==16{f=filename ".new"}

  when reading first line of first file, nr==1, or when reading 16th line of whatever file on, fnr==16, update f name of current file .new added end.

  for short example, transferred 2 lines instead of 15, used same code fnr==16 replaced fnr==3.

• print>f

  this prints current line file f.

  (if shell script, use >>. not shell script. awk.)

using glob specify file names

destination='media/user/directory/' awk 'nr==1 || fnr==16{close(f); f=filename ".new"} {print>f}'  "$destination"*.ascii