Points to consider while developing or running your test using Cygwin

• Cygwin is a free software but for MKS you need to buy the license.     
• Cygwin uses /dev/null and MKS uses nul.
• Cygwin follows Unix convention including line endings.
• UNAME returns Windows_NT in case of MKS but CYGWIN returns  CYGWIN_NT-6.1-WOW.
• UMASK: MKS seems to have problems with file/directory permissions, usually leaving permissions wide open or ill-defined. In case of CYGWIN it is much better.
• Administrator: MKS has had some problems being used by anyone other than the one who installed it, I'm not sure what this problem is. CYGWIN may or may not have this problem.
• Cygwin follows the POSIX standards. This means that paths are /cygdrive/c/. MKS PATH is the same as Windows PATH, using the ';' path separator character, and must be quoted if it has any embedded spaces. It can contain a mix of \\ and / file separator characters apparently.
• ENVIRONMENT VARIABLES: It appears that CYGWIN inherits Windows system variables with their names mapped to all uppercase, so things like windir, SystemDrive, SystemRoot, and MSDEVDIR, turn into WINDIR, SYSTEMDRIVE, SYSTEMROOT. The MKS shells don't have this behavior.