`shell'
-------

shell(COMMAND)
     :: Execute shell commands described by a string COMMAND.

RETURN
     integer

COMMAND
     string

     Execute shell commands described by a string COMMAND by a C
     function `system()'.  This returns the exit status of shell as its
     return value.

     [0] shell("ls");
     alg           da            katsura       ralg          suit
     algt          defs.h        kimura        ratint        test
     alpi          edet          kimura3       robot         texput.log
     asir.o        fee           mfee          sasa          wang
     asir_symtab   gr            mksym         shira         wang_data
     base          gr.h          mp            snf1          wt
     bgk           help          msubst        solve
     chou          hom           p             sp
     const         ifplot        proot         strum
     cyclic        is            r             sugar
     0
     [1]

