system("command") produces an error; but it works when invoked directly from Bash prompt
As mentioned system() creates a new standard shell sh and executes the commands. Since <() is a bash specific feature it can't be interpreted by sh.
You can circumvent this by calling bash explicitly and use the -c option:
system("bash -c \"diff <(cat /etc/passwd) <(ls -l /etc)\"");or using a raw string literal:
system(R"cmd(bash -c "diff <(cat /etc/passwd) <(ls -l /etc)")cmd");Here's the relevant part of the system(3) call manual page:
The
system()library function usesfork(2)to create a child process that executes the shell command specified in command usingexecl(3)as follows:execl("/bin/sh", "sh", "-c", command, (char *) 0);
system()returns after the command has been completed.
The system(3) call invokes /bin/sh to process the command. If you want specifically use bash features, you need to insert bash -c in front of the command string, which will run bash and tell it to process the remainder of the string.
system("bash -c \"diff <(cat /etc/passwd) <(ls -l /etc)\"");