Bash conditional fails when run in Jenkins pipeline script

Question

The following conditional works as expected when run from the bash command line on my Jenkins server:

if (($BRANCH_COUNT > 0)); then .....

But when running in the context of a Jenkins pipeline step (calling sh ''' .... '''), it writes an error and always evaluates to false. The error message (below) suggests maybe it's interpreting the value of $BRANCH_COUNT (in this case it is 1) as a command, which is then not found?

/var/jenkins/workspace/deploy-config-db-update@tmp/durable-baa54bb3/script.sh: 16: 
/var/jenkins/workspace/deploy-config-db-update@tmp/durable-baa54bb3/script.sh: 1: not found

Is there something different about the bash environment when run by the Jenkins sh command? Some special escaping or quoting needed?

Using `(())` is a bashism. Try `if test "$BRANCH_COUNT" -gt 0; then ...` — William Pursell, Jul 22 '20 at 20:20
Somewhat related: [Why does my bash code fail when I run it with sh?](https://stackoverflow.com/questions/15179446/why-does-my-bash-code-fail-when-i-run-it-with-sh) — that other guy, Jul 22 '20 at 20:22
William was right. Avoiding the bash-specific construction was the answer. — Mike Kantor, Jul 23 '20 at 15:15

score 1 · Answer 1 · answered Jul 23 '20 at 13:54

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if you use sh'''...''', the pipeline script variable will not be expanded in your shell script. You need to use sh """..."""

answered Jul 23 '20 at 13:54

Patrice M.

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I think it's something else. Other $VARIABLEs are being expanded within the triple-single-quoted script. – Mike Kantor Jul 23 '20 at 15:02
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Groovy (i.e. pipeline syntax) won't expand variables in (triple) single-quotes, but it will in (triple) double quotes. Of course, it you want bash to expand you variable,and not the pipeline script, then you want single quotes. – Patrice M. Jul 23 '20 at 19:50

score 1 · Answer 2 · answered Jul 24 '20 at 14:12

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Moving William Pursell's comment into an answer, because it solved the problem.

Using (()) is a bashism. Try if test "$BRANCH_COUNT" -gt 0; then ...

answered Jul 24 '20 at 14:12

Mike Kantor

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Bash conditional fails when run in Jenkins pipeline script

2 Answers2