From: shevegen@... Date: 2019-12-11T23:07:22+00:00 Subject: [ruby-core:96209] [Ruby master Bug#14413] `-n` and `-p` flags break when stdout is closed Issue #14413 has been updated by shevegen (Robert A. Heiler). My comment here is not primarily related to the threadstarter's comment, but indirectly. I am struggling a little bit in a cgi/www environment where debug is a bit difficult. The log files (from lighttpd) show broken pipes related to puts. I have not yet identified the cause of it, but I wanted to add that it is all a bit confusing to me as a ruby user right now. The first exposure I had was the "broken pipe" situation; even after googling for this (and also having found the issue here), it's still a bit frustrating to deal with. Any improvement in this regard in the future would be very useful, because I believe it is quite common for people to use ruby for different applications, including the www, GUI wrappers (such as ruby-gtk in my case), and of course my main use of ruby, in a commandline-linux situation. ---------------------------------------- Bug #14413: `-n` and `-p` flags break when stdout is closed https://bugs.ruby-lang.org/issues/14413#change-83101 * Author: josh.cheek (Josh Cheek) * Status: Feedback * Priority: Normal * Assignee: * Target version: * ruby -v: ruby 2.5.0preview1 (2017-10-10 trunk 60153) [x86_64-darwin16] * Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN ---------------------------------------- Ruby generally works well within a pipeline. The `-n` and `-p` flags are incredibly useful. However, it is common practice to use programs like `head` and `sed`, which will close the pipe after completing their job. This is convenient, because often it limits an expensive amount of output to a workable subset. I can figure out the pipeline for a subset of input, and then remove the limiting function. However, Ruby explodes with `-e:1:in `write': Broken pipe @ io_write - (Errno::EPIPE)`, when it writes the current line to stdout. When in a line oriented mode, and stdout closes, I think it should exit successfully (so it doesn't break bash scripts with `pipe fail`set) and silently (no error message), hence marking this a bug report rather than a feature request. I've attached a screenshot to show that this is how every other program works, that I tried. ~~~ git clone https://github.com/jquery/esprima cd esprima/test/fixtures/ ls | head -1 # ls find . -type f -name '*json' | head -1 # find find . -type f -name '*json' | head -1 | xargs cat | jq . | head -1 # jq find . -type f -name '*json' | grep -v JSX | grep -v tokenize | head -1 # grep find . -type f -name '*json' | sed -E '/JSX|tokenize/d' | head -1 # sed find . -type f -name '*json' | awk '/JSX|tokenize/ { next }; { print }' | head -1 # awk find . -type f -name '*json' | perl -e 'while(<>) { /JSX|tokenize/ || print }' | head -1 # perl find . -type f -name '*json' | ruby -ne 'print unless /JSX|tokenize/' | head -1 # ruby :( ~~~ ---Files-------------------------------- Screen Shot 2018-01-27 at 7.27.49 PM.png (458 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: