Until loop is used to execute a block of code until the expression is evaluated to be false. This is exactly the opposite of a while loop. While loop runs the code block while the expression is true and until loop does the opposite.
Exit When Any Command Fails This can actually be done with a single line using the set builtin command with the -e option. Putting this at the top of a bash script will cause the script to exit if any commands return a non-zero exit code.
while
takes a command to execute, so you can use the simpler
while ./runtest; do :; done
This will stop the loop when ./runtest
returns a nonzero exit code (which is usually indicative of failure).
To further simplify your current solution though, you should just change your untilfail script to look like this:
#!/bin/bash
while "$@"; do :; done
And then you can call it with whatever command you're already using:
untilfail ./runTest --and val1,val2 -o option1 "argument two"
If you don't want to wrap a complex pipe line into a shell script or function then this works:
while true; do
curl -s "https:..." | grep "HasErrors.:true"
if [[ "$?" -ne 0 ]]; then
break
fi
sleep 120
done
The HTTP request in this case always returns 200 but also returns some JSON which has an attribute "HasErrors":true when there is an error.
Having had a similar problem in a system that had shell retry logic duplicated everywhere I made a dedicated tool to solve this called "retry":
retry --until=fail ./runtest
A more complex example:
retry --until=fail --message="test succeeded" --delay=1 ./runtest
Tool available from https://github.com/minfrin/retry.
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