escapeshellarg escape a string to be used as a shell argument stringescapeshellarg stringarg escapeshellarg adds single quotes around a string and quotes/escapes any existing single quotes allowing you to pass a string directly to a shell function and having it be treated as a single safe argument. This function should be used to escape individual arguments to shell functions coming from user input. The shell functions include exec, system and the backtick operator. A standard use would be: See also exec, popen, system, and the backtick operator.