=over =item readpipe EXPR =item readpipe X EXPR is executed as a system command. The collected standard output of the command is returned. In scalar context, it comes back as a single (potentially multi-line) string. In list context, returns a list of lines (however you've defined lines with C or C). This is the internal function implementing the C operator, but you can use it directly. The C operator is discussed in more detail in L. If EXPR is omitted, uses C. =back