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br

Purpose

br stands for browse. This is a script that you kind of have to use to appreciate. It reads from stdin, stashes the data verbatim in a temporary file, launches vi on the file, and then removes the file when you're done. So it's a little bit like more/less but I think it's much more flexible and you have a full editor to play with. I think this was inspired by my time on Windoze when I had a script to launch notepad.exe on data coming from stdin. That was nice but had some issues and I like this better.

Alternatively, if you run it without redirecting stdin and give it one or more filenames, it launches vi in read-only mode. I used to have an alias for years that would only do read-only editing but I finally combined them together and the script has proven very useful. I often appreciate an extra safeguard to help keep me from changing a file by accident.

Syntax

Syntax: br [-g] [-n] [ [ OPTS ] FILENAME ... ]

Options and arguments

Option Description Default
-g --gvim Use {gvim} instead of vi/vim Available only on Windoze
-n --notepad Use Windoze {notepad} of vi/vim Available only on Windoze
-g --gedit Use {gedit} instead of vi Available only on Unix
  • If you supply one or more filenames, it invokes vi on the files in read-only mode.
  • If you don't supply any filenames, the script copies all the data from stdin into a temporary file and launches vi on that file.

Example

The script is too interactive to give a good example with just text. You can learn a lot by just trying it out. I've also created a desktop video to help.

Example from Linux shell

Click the image below to watch a video demonstrating the tool from Linux:

Linux example

Example from Windoze command prompt

Click the image below to watch a video demonstrating the tool from Windoze:

Windoze example

Notes

  • It is expected that you haven't redirected stdout. The script prints and error message and exits if this is not the case.

  • The Python tempfile.mkstemp() method is used to arrive at the temporary file name.

  • Signal handlers are set up to try to handle situations when the user used ctrl-C while the script is running to ensure the temporary file is removed.

  • I've definitely seen problems using br from Git bash on Windoze but I can't even start an interactive Python session from Git bash so I don't feel too bad. So I don't know how to fix this yet but maybe someday! I've basically given up trying to use the command on Git bash for now because it just falls flat on its face. I've gone back to alias br='vi -R' in Git bash because that's usually what I want to do.

  • I spent a bit of time trying to get this working on Windoze as well as Unix. I usually use cygwin for my shell on Windoze (which has its own pecularities with respect to paths outside of the cygwin domain, especially when notepad is used) but I think I also tested it from a regular Windoze command prompt.

  • You can specify options for vi such as a command to execute before giving you control. For example, to have it not wrap the lines, you could use:

    br -- -c'set nowrap' filename

    You could also type :set nowrap inside vi but this executes the command before opening vi.

    Notes:

    • The -- is very important - this tells br that its options are complete so the -c will be passed to vi
    • The lack of a space after -c is also significant. If you pass and operand to an option, you cannot leave any space or else br will think it's a filename and try to fully-qualify it