Unlike any other languages C is the most efficient language which has rich set of operators and due to its non-restrictions and generality makes it convenient for programming in many areas. In this post, i would like to show, how to create your own executable commands, like general shell commands i.e,
cp - copy command for copying files,
ls - for listing all enteries within a directory,
mv - command for moving files etc. This task is very simple.
Firstly create a C file using any editor with 'c' as extension at the end. For example, here i am using a vim editor and create a C file which prints anything you give.
vim printprogram.c
now i am going to write the following code in the created file
// program to print input
#include // library file
#define FILE_END EOF //symbolic constants
main() // start point
{
char k ; // variable declarations
printf("Enter & press Ctrl+D when finished:");
//getchar for input
while ( (k = getchar()) != FILE_END ) {
putchar(k); //output
}
} // end point
after coding the file, thus proceed for its working ie, compile the file by typing the following command in the terminal
cc printprogram.c -o printpg
'cc' is the complier or you can use 'gcc' since both are same. The option '-o ' is to copy the generated machine-executable code to a file print. Now check whether it runs by again typing in the terminal, the following command
./printpg
Here the ' . ' means current directory and ' ./ ' means inside the current directory to execute the file ' printpg '. If the file is running correctly then you can proceed to next step.
change the permission of the file
chmod -c 777 printpg
Now copy the file to the bin directory, where the executable files can be run without using ' ./ ' in the terminal.
sudo cp printpg /bin/
Remove the file print in your current directory
rm printpg
now just type print in the terminal
printpg
Atlast your executable file is ready to use.
