# common.lib
# Note no #!/bin/sh as this should not spawn an extra shell.
# It's not the end of the world to have one, but clearer not to.
#
BASEDIR=/home/steve/example

rename()
{
  # expects to be called as: rename .txt .bak [ srcdir/ [ destdir/ ] ] 
  FROM=$1
  TO=$2
  SRCDIR=$3
  DESTDIR=$4

  for i in ${SRCDIR}*$FROM
  do
    j=`basename $i $FROM`
    mv $i ${DESTDIR}${j}$TO
  done
}

rename .txt .bak /tmp/a/ /tmp/b/