C and script cannot co-operate-Very Weird

[hakermania]

Hi, I made this script which works perfectly:

clear
echo " 1 = Login

2 = Change the Login Password

3 = Forgot your password?

4 = Set the recall answer to question
"
read number
case $number in
1)
if [ -s /home/alex/Documents/PASS/password_PASS ]; then
existpass=`cat /home/alex/Documents/PASS/password_PASS`
echo "Type the existing pass:"
read givenpassasexisted
if [ "$existpass" == "$givenpassasexisted" ]; then
clear; echo "Success!"
else echo "Bad"
exit
fi
else echo "There is no password."

fi;;

2)
if [ -s /home/alex/Documents/PASS/password_PASS ]; then
existpass=`cat /home/alex/Documents/PASS/password_PASS`
echo "Type the existing pass:"
read givenpassasexisted
if [ "$existpass" == "$givenpassasexisted" ]; then
echo "Type new password:"
read newpass
cd /home/alex/Documents/PASS/
rm password_PASS
echo $newpass > /home/alex/Documents/PASS/password_PASS
echo $newpass > /home/alex/Documents/PASS/bringagain_PASS
else
echo "Wrong password.Plz retry"
fi
else echo "there is no password file.Create one plz."
fi;;
3)

echo "Which is your best friend?"
read maybebestfriend
realbestfriend=`cat /home/alex/Documents/PASS/recallquestion_PASS`
if [ "$maybebestfriend" == "$realbestfriend" ]; then
recall=`cat /home/alex/Documents/PASS/bringagain_PASS`
echo "The password which you forgot is $recall"
else
echo "Wrong answer to the question which is your best friend.Try again."
fi;;

4)
echo "Which is the current password?"
read givenpassasexisted
existpass=`cat /home/alex/Documents/PASS/password_PASS`
if [ "$existpass" == "$givenpassasexisted" ]; then
echo "Which is your best friend?"
read bestfriend
echo $bestfriend > /home/alex/Documents/PASS/recallquestion_PASS
else
echo "Wrong password.Try again!"
fi

esac
I also made a C program like this:

#include <stdlib.h>

int main()
{
system("/home/alex/Documents/PASS/hi");

return 0;
}
The problem is that when I type the script in console (./scriptname)
It works fine.When I call it via the C then it says
[: 67: popopo: unexpected operator

WHY?

[dwhitney67]

EDIT: Nevermind; I have my doubts that your script runs, even from the command line. I tested my two hypotheticals outlined below, and neither seemed to be an issue with a working script.

------------------------------
Perhaps you are missing the "#/bin/bash" in your script, or perhaps the script does not have the permissions to be executed?


P.S. Btw, there is an environment variable called $HOME that you should consider using in your script and C program. In a C program:


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

int main(void)
{
const char* home = getenv("HOME");
char buf[256];

if (home)
{
snprintf(buf, sizeof(buf) - 1, "%s/Documents/PASS/hi", home);
system(buf);
return 0;
}

fprintf(stderr, "HOME not defined.\n");
return -1;
}

[hakermania]

Scripts can run without the #/bin/bash from inside the terminal. Script runs normally when being run.
For example I run script via console:

root@lol-pc:/home/alex/Documents/PASS# ./hi
1 = Login

2 = Change the Login Password

3 = Forgot your password?

4 = Set the recall answer to question
1
Type the existing pass:
popopo
Success!
root@lol-pc:/home/alex/Documents/PASS#
Now, run the C program which calls the script:

root@lol-pc:/home/alex/Documents/PASS# password
1 = Login

2 = Change the Login Password

3 = Forgot your password?

4 = Set the recall answer to question

1
Type the existing pass:
popopo
[: 67: popopo: unexpected operator
Bad
root@lol-pc:/home/alex/Documents/PASS#
That's the real problem. It hasn't to do with #/bin/bash or something like that... ...
EDIT: Oh, and in line 67 the only thing that exists in the srcipt named "hi" is the "esac" command. nothing else....

[Barrucadu]

system() runs things with `sh`—I guess you're running your script in `bash`. Without even reading your script, I'm 99% certain there are some bashisms in it that `sh` doesn't like.

[hakermania]

Well. I confirm you for 3rd time that this is script works PERFECTLY when being run via console.

[hakermania]

OK, I now added the #/bin/bash
Still not working. Is one of the weirdest things I have ever seen!
Firstly, I run the script normally and works.Then I make A C program that calls the script and it misbehaves.
(To tell the truth I did not understand the Barrucadu. Plz explain)

[geirha]

Well. I confirm you for 3rd time that this is script works PERFECTLY when being run via console.

The POSIX [-command does not define the == operator, you want the = operator instead. Bash's builtin [-command however, does accept the == operator, which is the reason it is working when you run it from the terminal; without a she-bang, it will run it with the same shell it's invoked from. The system function (in C), runs the commands in /bin/sh, so your script will also be run with sh, since it's lacking a she-bang.


$ bash -c '[ "a" == "a" ] && echo works'
works
$ sh -c '[ "a" == "a" ] && echo works'
[: 1: a: unexpected operator


EDIT: You are missing the exclamation mark (!)


#!/bin/bash

[hakermania]

The POSIX [-command does not define the == operator, you want the = operator instead. Bash's builtin [-command however, does accept the == operator, which is the reason it is working when you run it from the terminal; without a she-bang, it will run it with the same shell it's invoked from. The system function (in C), runs the commands in /bin/sh, so your script will also be run with sh, since it's lacking a she-bang.


$ bash -c '[ "a" == "a" ] && echo works'
works
$ sh -c '[ "a" == "a" ] && echo works'
[: 1: a: unexpected operator


EDIT: You are missing the exclamation mark (!)


#!/bin/bash

So.....if I got it, you suggest to put = instead of ==?

[hakermania]

The POSIX [-command does not define the == operator, you want the = operator instead. Bash's builtin [-command however, does accept the == operator, which is the reason it is working when you run it from the terminal; without a she-bang, it will run it with the same shell it's invoked from. The system function (in C), runs the commands in /bin/sh, so your script will also be run with sh, since it's lacking a she-bang.


$ bash -c '[ "a" == "a" ] && echo works'
works
$ sh -c '[ "a" == "a" ] && echo works'
[: 1: a: unexpected operator


EDIT: You are missing the exclamation mark (!)


#!/bin/bash

Ok making the "==" "=" and adding the #!/bin/bash worked!
Thx.
But, can you explain me why it wasn't work with the C and was working when being run?

[geirha]

So.....if I got it, you suggest to put = instead of ==?

If you do that, your script will be POSIX compatible, as far as I can see (though your script is hard to read due to the bad indentation), and you can set the she-bang to #!/bin/sh .


But, can you explain me why it wasn't work with the C and was working when being run?

Because system() invokes the shell command with /bin/sh. In the terminal, you run /bin/bash (unless you've changed it from the default), so the script was being run with /bin/bash in the terminal, and with /bin/sh from C.

[hakermania]

Oh, got it. Interesting