usage: colsum [-d] [-t] [-kM] [-v] [-F field-separator] [-p
search-pattern] column [file]
options: -d  input and output in d3 format
         -t  input and output in time format
         -k  output in kB
         -M  output in MB
         -v  verbose output: show all lines
         -F  split fields at specfied pattern (default: white-space)
         -p  sum only lines which contain specfied pattern
example: ls -l | colsum -d 5