NEW
  PREFIX
AUTO 4,1
#!/bin/sh
#
# which
#
# locates a program in path
#

set -E

if [ -z $1 ]
    echo "USAGE: which program ..."
    exit 120
fi

set T = "${TEMP}which$$.tmp"
set A = 0
set F = 0
set S = 0
set L = 1

# get options
while [ ${L} -eq 1 ]
    if [ $1 = "-a" ] or [ $1 = "-A" ]
        set A = 1
        shift
    else
        if [ $1 = "-s" ] or [ $1 = "-S" ]
            set S = 1
            shift
        else
            set L = 0
        fi
    fi
loop

# split dirs in path
echo ${PATH} > ${T}
set L = `sed "s/:/ /" ${T}`
rm -q -c ${T}*

# find instances
while [ $# -gt 0 ]
    set F = ${F} + 1
    for D in ${L}
        # check for file
        if [ ${S} -eq 0 ]
            ls -f ${D}$1
            set T = $?
        else
            ls -f ${D}$1 > /dev/null
            set T = $?
        fi

        # process result
        if [ ${T} -eq 0 ]
            set F = ${F} - 1
            if [ ${A} -eq 0 ]
                break
            fi
        fi
    next
    shift
loop

# -s numeric result
if [ ${S} -gt 0 ]
    if [ ${F} -eq 0 ]
        exit 0
    else
        exit 70
fi

MAN
TEXT /BIN/which