Experiments in bash I/O redirection

Author: Craig Ringer

scripts/bash_io_redirection/experiment1.sh

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+#!/bin/bash
+
+# Open the log file we want to write to as FD 7
+exec {LOGFD}>/tmp/test.log
+
+# Open a new FD 8 that copies its input to FDs 7 and 1 (log file and stdout).
+# By using the FD instead of directly writing to the file, we help tee cope
+# with file position issues.  Hopefully.
+exec {DUPFD}> >(tee /dev/fd/${LOGFD} )
+
+# Send echo to fd1 (stdout). Result will only be on stdout.
+echo 'testing fd1'
+
+# Send echo to FD8. Result is going to be on on the log and on stdout. Hopefully.
+echo 'testing fd7' >&${DUPFD}
+
+# YESSSS
+
+# Now what about the other way? We want to copy stdout and stderr to a log file
+# along with script trace info, but also emit stdout to the terminal.
+#
+# So we need to open a log file:
+exec {LOGFD2}>/tmp/test2.log
+
+# copy stdout to the logfile via tee, retaining stdout too
+exec {STDOUTCOPY}> >(tee /dev/fd/${LOGFD2})
+