linux script running c program

Question

i tried to run a script in linux to run a c program the script was as follows

#!/bin/bash
`gcc odd.c -o odd222`
`chmod +x odd222`
echo `./odd222`

and odd.c is

main()
{
int i;
printf("enter the no.");
scanf("%d",&i);
printf("shiv");
}

but the problem is that when i run this script the all the scanf statement are executed then all the outputs are shown simentaniously....

if i do not put echo before ./odd222 then it says error enter command not found("enter" the first element in printf.

kindly help me

Answer 1

Here are few improvements:

Remove inverted quotes in your script, No need of them.

These are used when you want to store the return value of command in a variable.

Example:

var=`gcc odd.c -o odd222`
echo $var # this prints the gcc command output

Also run your executable without echo

gcc odd.c -o odd222
chmod +x odd222
./odd222

You can remove chmod line from your script as you have already changed the file to executable mode and there is no need of it everytime.

odd.c

#include <stdio.h>

int main()
{
  int i;
  printf("enter the no.");
  scanf("%d",&i);
  printf("shiv = %d", i);

  return 0;
}

Answer 2

For running a C language program using a gcc shell script, see the following:

It is also applicable to any language. Modify according to language and compiler.

Step 1:

Create any file having .sh extension (shell script)

For example: your_file_name.sh

Step 2:

Contents of file as follows:

gcc `pwd`/"$filename.c"

./"a.out"

Step 3:

Change permission for read, write, and execute file in terminal using the following command:

sudo chmod 777 filename.c

Step 4:

Execute file on terminal.

You must run the program from the directory where your source file is present because I have used the present working directory (if you want to select any spec).

./your_file_name.sh     filename.c

Example Screenshot:

Answer 3

You need not do to

echo `./odd222`

If you just write

./odd222

The shell tries to execute the program according to how it determines the file needs to be executed.Just make these changes,your code will work.

Putting echo returns a blank line on the display screen followed by the command prompt on the subsequent line. This is because pressing the ENTER key is a signal to the system to start a new line, and thus echo repeats this signal.

When you write

echo `./odd222`

it does not recognize the command.Hence it waits there only.echo has nothing to do with our program.

Answer 4

Get rid of the backticks, the chmod, and the echo. All you need to do is run gcc, then run your program.

#!/bin/bash
gcc odd.c -o odd222
./odd222

It'd also be good to only try to run the program if it compiles successfully. You can make it conditional by using &&.

#!/bin/bash
gcc odd.c -o odd222 && ./odd222

It'd also be good to modify your C code to ensure the printouts are printed immediately. Output is usually line buffered, meaning it's only displayed once you write a full line with a newline \n at the end. You'll want to either print a newline:

printf("enter the no.\n");

Or flush the output explicitly:

printf("enter the no.");
fflush(stdout);