Convert a Bash script to C

Linh · 04-23-2004, 11:33 AM

The short Bash script below works.

Code:

#!/bin/bash -p

inc=700
while true
do

lastcheckin=`date "+%s" -r /var/webofc/webofc.conf`
now=`date "+%s"`

if [[ $lastcheckin+$inc -lt $now ]]
then
   for i in `ps -ef |grep checkin2.sh |awk '{print $2}'`
   do
      lvi=`kill -9 $i`
   done
   /etc/checkin2.sh > /dev/null &
fi

sleep 300

done

/////////////////////////////////////////////////

The script above is being converted to C crudely. I got syntax error
probably because of where the semi-colon is suppose to be inserted.

Code:

#include <stdio.h>      /* standard library. a minimum requirement          */
#include <stdlib.h>     /* for oct_long = strtoul (six_oct_char, NULL, 8)   */

main ()

 {

   FILE *f;
   f = popen ("inc=700; "
              "while true "
              "do "
              "lastcheckin=`date \"+%s\" -r /var/webofc/webofc.conf` "
              "now=`date \"+%s\"` "
              "if [[ $lastcheckin + $inc < $now ]]; "
              "then for i in `ps -ef |grep checkin2.sh |awk '{print $2}'`; "
              "do "
              "lvi=`kill -9 $i` "
              "done "
              "/etc/checkin2.sh > /dev/null & "
              "fi ",
              "sleep 300 ",
              "done", "r");

   pclose(f);
 }

itsme86 · 04-23-2004, 12:04 PM

So basically you're just packing your script into an executable by using C? I think you want to use system() instead of popen().

Linh · 04-23-2004, 12:19 PM

Hi itsme86. Thank you for your response. Regardless of whether I used System or popen, it still complains about the syntax.

jtshaw · 04-23-2004, 12:52 PM

That is because it wants one string. ("blah" "blah") is not a valid constant char*

itsme86 · 04-23-2004, 01:00 PM

Quote:

Originally posted by jtshaw
That is because it wants one string. ("blah" "blah") is not a valid constant char*

You can append a \ at the end of the line to split strings like you're doing:

Code:

itsme@dreams:~/C$ cat splitstring.c
#include <stdio.h>

int main(void)
{
  puts("this is a " \
       "split string.");
  return 0;
}

itsme@dreams:~/C$ ./splitstring
this is a split string.

jlliagre · 04-25-2004, 12:51 PM

Linh,
some remarks on your C program:
- popen expects two arguments and you give it 4, remove the colons after "fi" and after "sleep ..."
- you use "r" as last argument, but fail to read the pipe output, so the script ends before having doing any jobs, I suggest you to use "w" instead.
- you must separate statements with semicolons, otherwise all your lines will be appended together without separators
- as it is, I see no advantage in front of the shell script it replaces ...

btw, "blah" "blah" is a valid constant equals to "blahblah" contrarily to what was answered previously..