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.
On Windows, escapeshellarg instead replaces percent signs, exclamation marks (delayed variable substitution) and double quotes with spaces and adds double quotes around the string. Furthermore, each streak of consecutive backslashes (\) is escaped by one additional backslash.
The argument that will be escaped.
The escaped string.