git/quote.h

#ifndef QUOTE_H
#define QUOTE_H

#include <stddef.h>

/* Help to copy the thing properly quoted for the shell safety.
 * any single quote is replaced with '\'', any exclamation point
 * is replaced with '\!', and the whole thing is enclosed in a
 * single quote pair.
 *
 * For example, if you are passing the result to system() as an
 * argument:
 *
 * sprintf(cmd, "foobar %s %s", sq_quote(arg0), sq_quote(arg1))
 *
 * would be appropriate.  If the system() is going to call ssh to
 * run the command on the other side:
 *
 * sprintf(cmd, "git-diff-tree %s %s", sq_quote(arg0), sq_quote(arg1));
 * sprintf(rcmd, "ssh %s %s", sq_quote(host), sq_quote(cmd));
 *
 * Note that the above examples leak memory!  Remember to free result from
 * sq_quote() in a real application.
 *
 * sq_quote_buf() writes to an existing buffer of specified size; it
 * will return the number of characters that would have been written
 * excluding the final null regardless of the buffer size.
 */

char *sq_quote(const char *src);
size_t sq_quote_buf(char *dst, size_t n, const char *src);

#endif