How to split a directory of files into sub-directories

Question

I have a directory full of files similar to these:

3260_661901_2008-2008.dat
3260_661901_2009-2009.dat
3260_661901_2010-2010.dat
3260_661901_2011-2011.dat
3260_661901_por-1998.dat
3260_662336_1999-1999.dat
3260_662336_2000-2000.dat
3260_662336_2001-2001.dat
3260_662336_2002-2002.dat

I would like to split off the files into directories names after the 6th and 7th character in the filename like this:

66/3260_661901_2008-2008.dat
66/3260_661901_2009-2009.dat
66/3260_661901_2010-2010.dat
66/3260_661901_2011-2011.dat
67/3260_671901_por-1998.dat
67/3260_672336_1999-1999.dat
67/3260_672336_2000-2000.dat
88/3260_882336_2001-2001.dat
88/3260_882336_2002-2002.dat

Is there a quick one liner command I can use to create the subdirectories and move the files into them?

I should mention the directory has over 33k files in it.

Answer 1

Assuming you are using bash you could run

for f in *.dat; do mkdir -p "${f:5:2}"; mv "$f" "${f:5:2}/"; done

or (if there are too many files for for f in *.dat to work)

while read f; do mkdir -p "${f:5:2}"; mv "$f" "${f:5:2}/"; done < ls

Answer 2

try

ls |  awk '{d=substr($0,6,2) ; printf "mkdir %s ; mv %s %s\n",d,$1,d }' | bash

• in this case, you can use ls result as input.

• you'll get error message as dir exists after first mkdir, to get rid use :

  awk '{d=substr($0,6,2) ; printf "test -d %s || mkdir %s ; mv %s %s\n",d,d,$1,d }'