# /tmp/prun
def prun '
    cmd =   \'$*\'
    idx =   index(cmd, "|") 
    idx2=   index(cmd, ">")
    if (idx2 && (!idx || idx2 < idx)) idx=idx2
    if (!idx) {
        unix(cmd)
        exit
    }

    rnum = rand()
    pfile="/tmp/pipe-" SPEC "." rnum
    rdef speccmd substr(cmd, 1, idx-1)
    unix(sprintf("/bin/rm -f %s", pfile)) ; on(pfile) ; offt
    cdef("cleanup_once", \
         "close(pfile); unix(sprintf(\"/bin/rm -f %s\", pfile)); ont; \
            unglobal pfile rnum;\n", "wdx")
    speccmd
    close(pfile) ; ont
    unix(sprintf("cat %s %s", pfile, substr(cmd,idx)))
    #unix(sprintf("/bin/rm -f %s", pfile) # done by cleanup_once
    unglobal pfile rnum
'