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POUnix script command not capturing stdin when launched as external process
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copied!<p>My situation is similar to <a href="https://stackoverflow.com/questions/220814/redirect-stdin-and-stdout-to-file?rq=1">Redirect Stdin and Stdout to File</a>. I want to run a program and capture the entire session (stdin and stdout) of running a program as though it had been run interactively from a terminal. </p> <p>From <a href="https://stackoverflow.com/questions/7564960/dump-terminal-session-to-file">Dump terminal session to file</a> I found out that the <code>script</code> command would work. Here is a simplified version of my program (written in Groovy) that does this.</p> <pre><code>import groovy.io.GroovyPrintWriter def OUTPUT_FILE = "output.txt" def sysout = new StringBuffer() def syserr = new StringBuffer() // On Linux (Ubuntu 12.04) - starts the bc command with script and capture session to OUTPUT_FILE Process proc = "script -q -f -c bc ${OUTPUT_FILE}".execute() // On OS X with a slightly different version of Script // Process proc = "script -q ${OUTPUT_FILE} bc".execute() proc.consumeProcessOutput(sysout, syserr) // Spawns separate threads that will consume the out to prevent overflow proc.withWriter { writer -> // Writes the following commands to the spawned process def gWriter = new GroovyPrintWriter(writer) // Imagine that the user enters these lines gWriter.println "a = 5" gWriter.println "b = 4" gWriter.println "c = a * b" gWriter.println "c" gWriter.println "quit" } proc.waitForOrKill(20000) // Give it 20 seconds to complete or kill the process println 'Standard out captured from process:\n' + sysout println 'Standard err captured from process:\n' + syserr </code></pre> <p>The program I wrote works on the version of script available on OS X. On OS X, the entire session is captured in the sysout variable and also written to the OUTPUT_FILE correctly.</p> <p><strong>Here's what I expect to get</strong></p> <pre><code>bc 1.06.95 Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc. This is free software with ABSOLUTELY NO WARRANTY. For details type `warranty'. a = 5 b = 4 c = a * b c 20 quit </code></pre> <p>However, <strong>here is what I get</strong> on Linux (Ubuntu 12.04), it omits everything that was typed into STDIN and only captures STDOUT. Here is the content of sysout and OUTPUT_FILE</p> <pre><code>bc 1.06.95 Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc. This is free software with ABSOLUTELY NO WARRANTY. For details type `warranty'. 20 </code></pre> <p>As you can see, the lines <code>a = 4, b = 5, etc</code> are missing.</p> <p>When I run the <code>script</code> command manually on Linux from the command line prompt (<code>script -q -f -c bc output.txt}</code> and enter the lines one by one, it works, i.e., all the lines are also written to OUTPUT_FILE.</p> <p>What additional steps do I need to do to get my program to work on Linux? I know that the program works on OS X so it is unlikely to be a problem with the program (or Groovy). I suspect that it must be something with how the Linux version of script behaves when launched as an external process.</p> <p>Any pointers would be appreciated.</p>

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