bash script style suggestions

[max-webster]

A few suggested changes for portability / modernization / robustness
of the BabelfishCompass.sh script:

I changed the shebang argument to '/usr/bin/env bash' for portability.
On some Mac and Linux systems, I've observed the preferred bash
being in /usr/bin, /usr/local/bin, or other locations other than /bin.
The /usr/bin/env idiom uses the first bash that is found in $PATH. Since
the script relies on $PATH to locate the 'java' executable, I presume that
type of flexibility is OK for this script.

Along the same lines, I used 'which' to determine the full path to the
java executable and assign that to ${JAVA}. To make debugging simpler
if ${JAVA} needs to be echoed later, e.g. to figure out if the right JDK/JRE
is being used.

I used $(...) notation instead of ... throughout. Backticks are considered
obsolete from a POSIX perspective. See http://mywiki.wooledge.org/BashFAQ/082
or https://unix.stackexchange.com/questions/126927/have-backticks-i-e-cmd-in-sh-shells-been-deprecated
for why $() is preferable.

I added quotes around "$?", for consistency with other 'if [[ ]]'
arguments in the script.

I changed sed to tr in the pipeline stage that deletes double quotes.
Just to simplify the action of getting rid of such-and-such characters,
without introducing the overhead of a regexp search and replace.

I changed $* to "$@" where shellscript arguments are passed through to 'java'.
That's a change recommended by the 'shellcheck' linter utility,
to avoid problems if some of the arguments contain spaces.

Signed-off-by: John Russell johrss@amazon.com

Description

Makes the script a little more portable (especially for Mac), maintainable, robust.
Reduces warnings from 'shellcheck' utility.

Issues Resolved

[List any issues this PR will resolve]

Check List

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[robverschoor]

ok