write

The write utility shall read lines from the standard input and write them to the terminal of the specified user. When first invoked, it shall write the message: to user name . When it has successfully completed the connection, the sender's terminal shall be alerted twice to indicate that what the sender is typing is being written to the recipient's terminal. Typing the erase and kill characters shall affect the sender's terminal in the manner described by the termios interface in XBD General Terminal Interface . Typing characters from LC CTYPE classifications print or space shall cause those characters to be sent to the recipient's terminal. When and only when the stty iexten local mode is enabled, the existence and processing of additional special control characters and multi-byte or single-byte functions is implementation-defined. Typing other non-printable characters shall cause implementation-defined sequences of printable characters to be written to the recipient's terminal. Lines to be copied to the recipient's terminal are read from standard input. Provide a default value for the internationalization variables that are unset or null. (See XBD Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) If set to a non-empty string value, override the values of all the other internationalization variables. Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments and input files). If the recipient's locale does not use an LC CTYPE equivalent to the sender's, the results are undefined. Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error and informative messages written to standard output. [XSI) ] ![[Option Start]]( Determine the location of message catalogs for the processing of LC MESSAGES. ![[Option End]]( If an interrupt signal is received, write shall write an appropriate message on the recipient's terminal and exit with a status of zero. It shall take the standard action for all other signals. The addressed user is not logged on or the addressed user denies permission. The write utility was included in this volume of POSIX.1-2017 since it can be implemented on all terminal types. The standard developers considered the talk utility, which cannot be implemented on certain terminals, to be a "better" communications interface. Both of these programs are in widespread use on historical implementations. Therefore, the standard developers decided that both utilities should be specified. This utility is marked as part of the User Portability Utilities option. The normative text is reworded to avoid use of the term "must" for application requirements. The write utility is moved from the User Portability Utilities option to the Base. User Portability Utilities is now an option for interactive utilities.