scanpty

#!/bin/sh
#
# A shell/awk script to find out your range of pseudo-ttys

# If BSD pseudo-ttys exist, /dev/pty?? is sure to exist.
# What do we do if we don't find anything??
exists=`echo /dev/pty??`
if [ "$exists" = "/dev/pty??" ]; then
	echo "PTYCHAR=\\\"\\\""
	echo "HEXDIGIT=\\\"\\\""
	exit 0
fi

# Make sure we have system directories in our path.
PATH=$PATH:/bin/usr/bin

# First, make sure we have awk.
haveawk=`echo yes | (exec 2>/dev/null; awk '{print $1}')`
if [ "$haveawk" != "yes" ]
then   # No awk, select a default set of ptys.
	echo "PTYCHAR=\\\"pqrstuvwxyzPQRST\\\""
	echo "HEXDIGIT=\\\"0123456789abcdef\\\""
	exit 0
fi

# Well, there are ptys and we have awk, find the range.
echo $exists | awk '
BEGIN	{ RS=" "; printf "PTYCHAR=\\\""; }
        { c=substr($1, 9, 1); 
	  if (range[c] == 0) { ++range[c]; printf "%s", c; }
	}
END	{ printf("\\\"\n"); }'
echo $exists | awk '
BEGIN	{ RS=" "; printf "HEXDIGIT=\\\""; }
	{ c=substr($1, 10, 1); 
	  if (range[c] == 0) { ++range[c]; printf "%s", c; }
	}
END	{ printf("\\\"\n"); }'
exit 0