<P>The account-module is responsible for maintaining the user database. It automatically handles tasks like registration, authentication, access control, password retrieval, user settings and much more.</P>
<P>The required administration can be accomplished through the "account" interface of the administration section. From here administrators can get a quick overview of all registered users and view/edit specific accounts using the links provided. Some useful operations include blocking specific accounts (e.g. a troublesome user) and giving/taking administration permissions. Note that you should only give these permissions to people you trust!</P>
<P>Check the documentation page for detailed information about user management.</P>
<P>A <I>regular expression</I> (or <I>regexp</I>, or <I>pattern</I>) is a text string that describes some (mathematical) set of strings. A regexp <CODE>R</CODE> "matches" a string <CODE>S</CODE> if <CODE>S</CODE> is in the set of strings described by <CODE>R</CODE>.</P>
<P>Regular expressions are very powerful but often get complicated and nothing in this write-up can change that.
<P>A complete explanation of regular expressions is beyond the scope of this help system. A regular expression may use any of the following special characters/constructs:</P>
<TABLE BORDER="1">
<TR><TD>^</TD><TD>Matches the beginning of a string.<TD></TR>
<TR><TD>$</TD><TD>Matches the end of a string.<TD></TR>
<TR><TD>.</TD><TD>Matches any character (including newline). For example the regular expression a.c would match the strings abc, adb, axb, but not axxc.<TD></TR>
<TR><TD>a*</TD><TD>Matches any sequence of zero or more a characters.</TD></TR>
<TR><TD>a+</TD><TD>Matches any sequence of one or more a characters.</TD></TR>
<TR><TD>a?</TD><TD>Matches either zero or one a character.</TD></TR>
<TR><TD>ab|cd</TD><TD>Matches either of the sequences "ab" or "cd".</TD></TR>
<TR><TD>(abc)*</TD><TD>Matches zero or more instances of the sequence abc.</TD></TR>
<TR><TD>[abc]</TD><TD>Matches any one of the characters between the brackets: a, b or c. Ranges of characters can specified by using a hyphen. For example, the regular expression [0-9] means match any digit. Multiple ranges can be specified as well. The regular expression [A-Za-z] means match any upper or lower case letter. To match any character except those in the range, the complement range, use the caret as the first character after the opening bracket. For example, the expression [^269A-Z] will match any characters except 2, 6, 9, and upper case letters.</TD></TR>
<TR><TD>{num}</TD><TD>Matches the preceding element num times.</TD></TR>
<TR><TD>{min, max}</TD><TD>Matches the preceding element at least min times, but not more than max times.</TD></TR>
</TABLE>
<P><B>Examples:</B></P>
<TABLE BORDER="1">
<TR><TD>apple</TD><TD>Matches any string that has the text "apple" in it.<TD></TR>
<TR><TD>^apple$</TD><TD>Matches the exact string "apple".<TD></TR>
<TR><TD>^apple</TD><TD>Matches any string that starts with "apple".<TD></TR>
$output .= form_select(t("Public accounts"), "account_register", variable_get("account_register", 1), array("Disabled", "Enabled"), "If enabled, everyone can create a new user account. If disabled, new user accounts can only be created by site administrators.");
if (empty($user[real_email]) || (!check_mail($user[real_email]))) $error = t("the e-mail address '$user[real_email]' is not valid");
if (empty($user[userid]) || (!check_name($user[userid]))) $error = t("the username '$user[userid]' is not valid");
if (strlen($user[userid]) > 15) $error = t("the username '$user[userid]' is too long: it must be less than 15 characters");
// Check to see whether the username or e-mail address are banned:
if ($ban = user_ban($user[userid], "username")) $error = t("the username '$user[userid]' is banned") .": <I>$ban->reason</I>";
if ($ban = user_ban($user[real_email], "e-mail address")) $error = t("the e-mail address '$user[real_email]' is banned") .": <I>$ban->reason</I>";
// Verify whether username and e-mail address are unique:
if (db_num_rows(db_query("SELECT userid FROM users WHERE LOWER(userid) = LOWER('$user[userid]')")) > 0) $error = t("the username '$user[userid]' is already taken");
if (db_num_rows(db_query("SELECT real_email FROM users WHERE LOWER(real_email) = LOWER('$user[real_email]')")) > 0) $error = t("the e-mail address '$user[real_email]' is already in use by another account");
return "\"$edit[text]\" ". (($rule = user_ban($edit[text], $edit[category])) ? "matched with access rule '$rule->mask'" : "did not match any of the existing access rules") .".";
$subject = strtr(t("Account details for %a"), array("%a" => variable_get(site_name, "drupal")));
$message = strtr(t("%a,\n\n\nsomeone signed up for a user account on %b and supplied this e-mail address as their contact. If it wasn't you, don't get your panties in a knot and simply ignore this mail. If this was you, you will have to confirm your account first or you will not be able to login. To confirm your account visit the URL below:\n\n %c\n\nOnce confirmed you can login using the following username and password:\n\n username: %a\n password: %d\n\n\n-- %b team\n"), array("%a" => $edit[userid], "%b" => variable_get(site_name, "drupal"), "%c" => $link, "%d" => $edit[passwd]));
$queries = array(array("users recently visiting", "ORDER BY last_access DESC"), array("users recently joining", "ORDER BY id DESC"), array("users with access rights", "WHERE access != '' ORDER BY last_access DESC"), array("users with pending accounts", "WHERE status = 1 ORDER BY last_access DESC"), array("users with blocked accounts", "WHERE status = 0 ORDER BY last_access DESC"));
