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https://issues.apache.org/jira/browse/NIFI-1786?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15248456#comment-15248456
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Brandon DeVries edited comment on NIFI-1786 at 4/19/16 7:33 PM:
----------------------------------------------------------------
So, realizing that what happened there was that strict mode was causing the
check in the script for the existence of $MAX_FD to fail. However, it does not
appear to be being done in the best way. Some guy named Greg on the internet
says the way it is being done now is "Only needed for ancient Bourne shells and
not so ancient pdksh or ash versions. Don't use this in modern scripts." \[1\].
Consulting StackOverflow \[2\] \[3\]\[4\] gives us another option that is
compatible with set -u:
{code}
if [ -n "${foobar+1}" ]; then
echo "foobar is defined"
else
echo "foobar is not defined"
fi
{code}
\[1\] http://mywiki.wooledge.org/BashFAQ/083
\[2\]
http://unix.stackexchange.com/questions/56837/how-to-test-if-a-variable-is-defined-at-all-in-bash-prior-to-version-4-2-with-th
\[3\]
http://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash
\[4\]
https://www.gitbook.com/book/tra38/essential-copying-and-pasting-from-stack-overflow
was (Author: devriesb):
So, realizing that what happened there was that strict mode was causing the
check in the script for the existence of $MAX_FD to fail. However, it does not
appear to be being done in the best way. Some guy named Greg on the internet
says the way it is being done now is "Only needed for ancient Bourne shells and
not so ancient pdksh or ash versions. Don't use this in modern scripts." \[1\].
Consulting StackOverflow \[2\] \[3\] gives us another option that is
compatible with set -u:
{code}
if [ -n "${foobar+1}" ]; then
echo "foobar is defined"
else
echo "foobar is not defined"
fi
{code}
\[1\] http://mywiki.wooledge.org/BashFAQ/083
\[2\]
http://unix.stackexchange.com/questions/56837/how-to-test-if-a-variable-is-defined-at-all-in-bash-prior-to-version-4-2-with-th
\[3\]
http://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash
> Use "Unofficial Bash Strict Mode" in nifi,sh
> --------------------------------------------
>
> Key: NIFI-1786
> URL: https://issues.apache.org/jira/browse/NIFI-1786
> Project: Apache NiFi
> Issue Type: Improvement
> Reporter: Brandon DeVries
> Priority: Minor
>
> We just had a user trying to do "nifi.sh start" on a new install get the
> cryptic error message
> {code}
> does not exist. Exiting.
> {code}
> enabling "Unofficial Bash Strict Mode"\[1\] by adding
> {code}
> set -euo pipefail
> {code}
> to the top of the script revealed that the problem was that $MAX_FD was
> unset. While we're still working through why that would be, its at least a
> bit more to go on.
> \[1\] http://redsymbol.net/articles/unofficial-bash-strict-mode/
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