A2osX/BIN/WHICH.txt

#!/bin/sh
#
# which
#
# locates a program in path
#

set -E

if [ -z $1 ] or [ $1 = "-h" ] or [ $1 = "-H" ]
    echo "Usage : which [options] program ..."
    echo "   -A show all found"
    echo "   -S no output, 0 if found, 1 if not"
    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 [ -f ${D}$1 ]
            set T = 0
        else
            set T = 1
        fi

        # process result
        if [ ${T} -eq 0 ]
            if [ ${S} -eq 0 ]
                echo "${D}$1"
            fi

            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