BCHM 4400 Lecture Notes - Lecture 4: File Descriptor, Subroutine, Standard Streams
29 Jan 2018
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I/o file handles: file handle: name of i/o connection for perl program. Often uppercase letters are used to name: 6 file handles for perl: : used to read from standard input stream. Every time it is used, perl reads next line from input. All the way up to the next line: undef is returned if the end of the input is reached. Standard output (stdout: print operator: takes list of items and sends each as a string to stdout. Data: _end_: indicates perl code is finished. What follows is the input data: data file handle: used to read lines of input data. Using, opening and closing file handles: opening: Can open file handle for input and output. Can open file handle for input and output: using: Lines can be read from file handle just as from stdin. File handle open for writing can be used with print(: closing: When finished w file handle, close it using the close()
