#!/bin/bash
## arr -- much like the Mantes arrange-command -- by Eugene Reimer 2001-oct;
##	obsoletes several of my earlier scripts:  dbl,  colswap;
##
## USAGE EXAMPLES:
##	arr 2 1			--a filter to swap columns, for a 2-column file
##	arr 1 1			--a filter to "double" a 1-column file
##	arr 3 2 1		--a filter to column-reverse a 3-column file
##	arr -F'\t' 2 1		--like first example but with TAB-separated fields;  by default they are SPACE-or-TAB-separated
##	K=$(wc F |arr 1)	--get number-of-lines in file F
##
## Copyright © 2001,2011 Eugene Reimer;  can be used, modified, copied, and distributed or sold under the terms of either the LGPL or the GPL (your choice);
## see http://www.gnu.org/licenses for the details of these terms.

S=' '
[ $# -eq 0 ] && { echo "usage:  arr [-F FLDSEP]  column-nbrs"; exit; }
if   [[ $1 == -F  ]];then S="$2"; shift 2
elif [[ $1 == -F* ]];then S="${1#-F}"; shift
fi
s='{print $'"$1";  shift
for x do
  s="$s"' "	"'
  if [[ $x == [0-9]* ]]; then	s="$s"' $'"$x"
  else				s="$s \"$x\""
  fi
done
s="$s}"
##echo "awk -F\"$S\" $s"		##debug
awk -F"$S" "$s"


exit
2004-feb:  added support for non-numeric literals between column-nbrs;  literals & columns are separated by TAB-chars
2011-mar:  finally added -F support;