Left to Right

# check for leading slash
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; [[ ${NAME%%/*} = "" ]] && echo "Have leading slash"
Have leading slash

# strip_leading_slashes (or just: ${NAME#/} )
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME#/*}
usr/lib/sux_1.0.1-3.2.tar.gz

# right_of_first_period
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME#*.}
0.1-3.2.tar.gz

# right_of_first_slash
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME#*/}
usr/lib/sux_1.0.1-3.2.tar.gz

# left_of_first_period
 NAME=usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME%%.*}
usr/lib/sux_1

# left_of_first_slash

 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME%%/*}
(returns null)

 NAME=usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME%%/*}
usr

Right to Left

# check for trailing slash

bash-3.1# NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; [[ ${NAME##*/} = "" ]] && echo "Have trainling slash"
bash-3.1# NAME=/usr/lib/sux_1.0.1-3.2.tar.gz/ ; [[ ${NAME##*/} = "" ]] && echo "Have trainling slash"
Have trainling slash


# strip_trailing_slashes
NAME=/usr/lib/ ; echo ${NAME%/}
/usr/lib

# right_of_last_period
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME##*.}
gz

# left_of_last_period
NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME%.*}
/usr/lib/sux_1.0.1-3.2.tar

# right_of_last_slash
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME##*/}
sux_1.0.1-3.2.tar.gz

# left_of_last_slash
 NAME=/usr/lib/sux_1.0.1-3.2.tar.gz ; echo ${NAME%/*}
/usr/lib