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    <p>You can use interpreted languages like Perl, Python, or Ruby to call an <code>ioctl</code> to the kernel for querying drive status.</p> <pre><code>function check_disk_tray_perl { perl -e 'use POSIX; sysopen(FD, $ARGV[0], O_RDONLY|O_NONBLOCK) || die "Failed to open device ${ARGV[0]}\n"; my $r = ioctl(FD, 0x5326, 0); exit ($r &gt; 0 ? $r &amp; 0x01 ? 0 : 1 : 2);' "$1" } function check_disk_tray_ruby { ruby -e 'require "fcntl"; dev = ARGV[0]; begin fd = IO::sysopen(dev, Fcntl::O_RDONLY|Fcntl::O_NONBLOCK); io = IO.new(fd); rescue; $stderr.puts "Failed to open device #{dev}."; exit 2; end; r = io.ioctl(0x5326, 0); exit (r &gt; 0 ? (r &amp; 0x01) == 1 ? 0 : 1 : 2);' "$1" } function check_disk_tray_python { python -c 'import os, sys, fcntl dev = str(sys.argv[1]) try: fd = os.open(dev, os.O_RDONLY|os.O_NONBLOCK) except: sys.stderr.write("Failed to open device " + dev + ".\n") exit(2) r = fcntl.ioctl(fd, 0x5326, 0) os.close(fd) exit(2 if (r &lt;= 0) else 0 if (r &amp; 1) else 1) ' "$1" } </code></pre> <p>You could also compile a code with gcc on runtime:</p> <pre><code>function check_disk_tray_gcc { local OUTPUT_BINARY="/tmp/check_disk_tray_gcc_$((RANDOM))" local FLAGS=(-O2 -pipe -fomit-frame-pointer) local R gcc "${FLAGS[@]}" -o "$OUTPUT_BINARY" -xc - &lt;&lt;EOF #include &lt;stdio.h&gt; #include &lt;sys/ioctl.h&gt; #include &lt;sys/types.h&gt; #include &lt;sys/stat.h&gt; #include &lt;fcntl.h&gt; #include &lt;linux/cdrom.h&gt; int main(int argc, char** argv) { if (argc != 2) { fprintf(stderr, "Invalid number of arguments.\n"); return 2; } char* file = argv[1]; int fd = open(file, O_RDONLY|O_NONBLOCK); if (fd &lt; 0) { fprintf(stderr, "Failed to open file %s.\n", file); return 2; } int r = ioctl(fd, CDROM_DRIVE_STATUS, 0); return (r &gt; 0 ? r &amp; 1 ? 0 : 1 : 2); } EOF if [[ $? -ne 0 || ! -f "$OUTPUT_BINARY" ]]; then R=2 else "$OUTPUT_BINARY" "$1" R=$? fi rm -f "$OUTPUT_BINARY" return "$R" } </code></pre> <p>Wrapper function:</p> <pre><code>function check_disk_tray { if type -P perl &gt;/dev/null; then check_disk_tray_perl "$1" elif type -P ruby &gt;/dev/null; then check_disk_tray_ruby "$1" elif type -P python &gt;/dev/null; then check_disk_tray_python "$1" elif type -P gcc &gt;/dev/null; then check_disk_tray_gcc "$1" else echo "No tool usable for checking disk tray." &gt;&amp;2 return 2 fi } </code></pre> <p>Example usage:</p> <pre><code>#!/bin/bash # ---- Place the above codes here. ---- check_disk_tray "$(readlink -f /dev/cdrom)" case "$?" in 0) echo "Tray is closed." ;; 1) echo "Tray is open." ;; 2|*) echo "General failure." ;; esac </code></pre>
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    1. COI was able to get this to work however I had to substitute `dev = str(sys.argv[1])` with `dev = str("/dev/cdrom")`
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    2. CO@user2740987 I tried the python script again and it worked unmodified. What was the problem?
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