Shell Programming and Scripting

> perl_src.c_pl ${fl} || { echo "$?, wrong;"; }
Can't use an undefined value as a symbol reference at ./perl_src.c_pl line 254, <$sdx> line 1013.
2, wrong;
>
>   # now execute the same command by the C-with system();
> t_sys "perl_src.c_pl ${fl} || { echo \"$?, wrong;\"; } "
Can't use an undefined value as a symbol reference at perl_src.c_pl line 254, <$sdx> line 1013.
0, wrong;

 executed command: perl_src.c_pl ../data/sdx4-1K.dat || { echo "0, wrong;"; }
 RETURN: 0
>

> cat t_sys.c
#include <stdio.h>
main ( int argc, char* argv[] )
{
  char *cmd=argv[1];
  int rt=system(cmd);
  printf ("\n executed command: %s\n RETURN: %d\n", cmd, rt);
}
>

exit 5;

$ sh -c 'perl -e "exit 5" || echo perl exit status $?'
perl exit status 5
$ echo sh exit status $?
sh exit status 0

sh -c 'perl ....; pexit=$?; [ $pexit -ne 0 ] && echo $pexit; exit $pexit'

t_sys "perl_src.c_pl ${fl} || { echo \"$?, wrong;\"; } "

> sh -c 'perl -e "exit 5;" || exit $? ' ; echo $?
5
> t_sys 'perl -e "exit 5;" || exit $? ' ; echo $?

 executed command: perl -e "exit 5;" || exit $?
 RETURN: 1280
2
>

#include <stdio.h>
main ( int argc, char* argv[] )
{
  char *cmd=argv[1];
  int rt=system(cmd);
  int actual_exit = -1, actual_signal = -1;
  if (WIFEXITED(rt)) actual_exit = WEXITSTATUS(rt);
  else actual_signal = WTERMSIG(rt);
  printf ("\n executed command: %s\n RETURN: %d or SIGNAL: %d\n", 
    cmd, actual_exit, actual_signal);
  return actual_exit;
}

#include <stdio.h>
#include <stdlib.h>

int
main(int argc, char *argv[])
{
    char *cmd=argv[1];
    int rt=system(cmd);
    if (WIFEXITED(rt)) {
        rt=WEXITSTATUS(rt);
        printf ("\n executed command: %s\n RETURN: %d\n", cmd, rt);
    }
    else
        rt=128;
    return rt;
}

$ ./a.out 'perl -e "exit 5"'; echo $?

 executed command: perl -e "exit 5"
 RETURN: 5
5