1.3.9

• Implement linkage for Linux (@sjackman)
• Remove unused writer methods for Hbc.caskroom and Hbc.cache. (@reitermarkus)
• x11_requirement: remove custom minimum version. (@MikeMcQuaid)
• Utils.popen_read: Nonexistent program should fail (@sjackman)
• config: Print the linked_version [Linux] (@sjackman)
• Fix SystemCommand escaping … again. (@reitermarkus)
• lines_cop: Convert ARGV audit to negative look ahead (@GauthamGoli)
• Fix a test failure when svn is not installed (@sjackman)
• Hardware::CPU: Implement OS-agnostic methods (@sjackman)
• Unify proxy documentation. (@MikeMcQuaid)
• version/null: add to_i method. (@MikeMcQuaid)
• cleaner_spec: have a single "cleans files" test. (@MikeMcQuaid)
• Include SSH_AUTH_SOCK in filtered environment (@Noctem)
• vendor-install: Add ARM bottle for portable-ruby (@sjackman)
• Properly upgrade Casks with version :latest (@amyspark)
• Adding proxy variables to FILTERED_ENV (@barreyra)
• Fix external Cask commands. (@reitermarkus)
• whitelisting additional SentinelOne dylib pattern (@lbergelson)
• Whitelist SUDO_ASKPASS environment variable. (@reitermarkus)
• Only show kext caveat on High Sierra or above. (@reitermarkus)
• Fix Utils::Shell.parent. (@reitermarkus)
• Refactor caveats and add kext caveat. (@reitermarkus)
• Implement brew cask upgrade (@amyspark)
• bin/brew: don't set empty, unfiltered variables. (@MikeMcQuaid)
• Enable environment filtering for developers. (@MikeMcQuaid)
• More environment filtering fixes (@MikeMcQuaid)
• Allow optionally using Homebrew's curl (@MikeMcQuaid)
• Cleaner: ELF files are executable on Linux (@sjackman)
• Add CVSRequirement and SubversionRequirement (@sjackman)
• formula_installer: force fewer default formulae (@MikeMcQuaid)
• setup-analytics: Handle missing /proc/.../uuid (@sjackman)
• lines_cop: Add condition to prevent false positives (@GauthamGoli)
• Fix SystemCommand escaping. (@reitermarkus)
• Change the generic bottle tag to processor-system (@sjackman)
• Installing casks is supported only on macOS (@sjackman)
• Cask doctor: add macOS & Java versions (@commitay)
• bump-formula-pr: fix for when hub isn't configured (@ilovezfs)