gotee

README

tee (gotee)

An implementation of tee in Go.

This program, an implementation of the tee command, first available in 1974, takes in standard input and for each file specified either appends or writes to each file until the standard input is done. As it does so it passes out what is read to standard output.

The tee command is a handy way, and one of the only ways to branch standard input to save to one or more files and to reproduce standard input as standard output for consumers down the line. Additionally, to allow for the avoidance of redirecting standard output to /dev/null, the -S option allows for the avoidance of carry-over of standard input to standard output. This is not something I have seen on any other implementations.

Usage

• gotee -h print usage
• gotee no files specified - use keyboard input instead of stdin and exit on Control-C
• gotee <file1> <file2> - write to one or more files specified as last arguments
• gotee -a <file> <file> - append to existing files and if not existing create new files
• gotee -S <file> <file> - do not forward standard input to standard output
• gotee -i - ignore interrupt. Not implemented but is in original tee
  • I don't quite know what to do with this. If an interrupt is received that means that whatever is piping to standard input would have been shut down and therefore there would be no standard input to recieve. I would be happy to be corrected on this. In theory I could make the loop through standard input a function internal to main and restart that function on interrupt, but I don't see the point of that. What I have done is in all cases intercept an interrupt signal and shut things down as gracefully as possible.

Notes

The official tee waits for stdin even when nothing has been sent to it. I've added support for waiting on keyboard input for string data. Control-C works to exit this. So although this is reading input as a string, this is likely not harmful. The main stdin reader reads in bytes and thus can handle cat test.jpg | gotee -S out.jpg.

This works to mimic command | gotee -S out.txt

command | dd status=none of=out.txt

Notes

The argument parsing library used here does not deal with arguments such as -1, -2, -, etc. It may be that an argument will need to have a different identifier to work around this.

-- Ian Marsman