HOME=/usr/xyz
SHELL=~/bash
echo ~ch\et
echo ~/"foo"
echo "~chet"/"foo"
echo \~chet/"foo"
echo \~chet/bar
echo ~\chet/bar
echo ~chet""/bar
echo ":~chet/"
echo abcd~chet
echo "SHELL=~/bash"
echo $SHELL
echo abcd:~chet
path=/usr/ucb:/bin:~/bin:~/tmp/bin:/usr/bin
echo $path

cd /usr
cd /tmp
echo ~-
echo ~+

XPATH=/bin:/usr/bin:.

# yes tilde expansion
PPATH=$XPATH:~/bin
echo "$PPATH"

# no tilde expansion
PPATH="$XPATH:~/bin"
echo "$PPATH"

# yes tilde expansion
export PPATH=$XPATH:~/bin
echo "$PPATH"

# no tilde expansion
export PPATH="$XPATH:~/bin"
echo "$PPATH"