Label a line in the script for the transfer of control by b or t. label may contain up to seven characters. (The POSIX standard says that an implementation can allow longer labels if it wishes to. GNU sed allows labels to be of any length.)
Write to standard output the line number of addressed line.
Append text following each line matched by address. If text goes over more than one line, newlines must be “hidden” by preceding them with a backslash. The text will be terminated by the first newline that is not hidden in this way. The text is not available in the pattern space and subsequent commands cannot be applied to it. The results of this command are sent to standard output when the list of editing commands is finished, regardless of what happens to the current line in the pattern space.
Transfer control unconditionally (branch) to :label elsewhere in script. That is, the command following the label is the next command applied to the current line. If no label is specified, control falls through to the end of the script, so no more commands are applied to the current line.
Replace (change) the lines selected by the address with text. When a range of lines is specified, all lines as a group are replaced by a single copy of text. The newline following each line of text must be escaped by a backslash, except the last line. The contents of the pattern space are, ...