Timothy Potter told me offline that with the original patch, bin/solr healthcheck -c whatever fails when the war has not yet been unpacked. I reproduced:
$ bin/solr healthcheck -c testing
bin/solr: line 386: /Library/Java/JavaVirtualMachines/jdk1.8.0_20.jdk/Contents/Home/bin/jar xf: No such file or directory
Error: Could not find or load main class org.apache.solr.util.SolrCLI
This patch fixes that problem, and also switches from using command -v to hash to check for executables, which the above-linked SO answer says is the best way from bash scripts (which bin/solr is).
This patch also renames $unzipCommand to $UNPACK_WAR_CMD, and adds -q to the unzip command, so that it's quiet (like jar xf is).