Execl System Call: Execute Programs in Unix/Linux

Execl is a system call in Unix and Unix-like operating systems that allows a process to replace its current program with a new program. The execl function is used to execute a program file specified by a pathname. When execl is called, the current process is replaced by the specified program. The new program takes over the memory space, file descriptors, and environment of the calling process.

The syntax for execl is:

int execl(const char *path, const char *arg0, ..., const char *argn, (char *)NULL);

Here, 'path' is the path to the program to be executed, and 'arg0' to 'argn' are the arguments to the program. The last argument, '(char *)NULL', is necessary to terminate the argument list. The execl function returns -1 if it fails to execute the specified program.