paths='/bin /usr/bin /usr/local/bin /usr/ucb /usr/local /usr/lbin'
paths="$paths /opt/bin /opt/local/bin /opt/local /opt/lbin"
paths="$paths /usr/5bin /etc /usr/gnu/bin /usr/new /usr/new/bin /usr/nbin"
paths="$paths /opt/gnu/bin /opt/new /opt/new/bin /opt/nbin"
paths="$paths /sys5.3/bin /sys5.3/usr/bin /bsd4.3/bin /bsd4.3/usr/ucb"
paths="$paths /bsd4.3/usr/bin /usr/bsd /bsd43/bin /usr/ccs/bin"
paths="$paths /etc /usr/lib /usr/ucblib /lib /usr/ccs/lib"
paths="$paths /sbin /usr/sbin /usr/libexec"
paths="$paths /system/gnu_library/bin"
        
for p in $paths
do  
        case "$p_$PATH$p_" in
        *$p_$p$p_*) ;;
        *) test -d $p && PATH=$PATH$p_$p ;;
        esac
done