> This seems similar to the way command like arguments work on windows. The previous poster overstates things. Environment variables passed to the process by t

> This seems similar to the way command like arguments work on windows. The previous poster overstates things. Environment variables passed to the process by the kernel[1] are NUL-delimited, including a double-NUL (or zero-length pair) to terminate the list of name=value pairs. Neither is there any syntactical ambiguity, as within each NUL-terminated pair the first '=' character delimits the variable name from the value, regardless of whether there are subsequent '=' characters. So there's no real parsing of the name=value content, only locating each NUL character in turn as a C array is built up by the entry code. The only limitation is that neither names nor values can contain the NUL character, and names cannot contain a '=' character. The process startup code uses the exact same logic for constructing argv as it does for constructing environ/envp as they're both passed by the kernel in the same manner, including the same NUL-delimited structure. In fact, they're written as one long, serial sequence to the stack, above or beneath (depending on stack direction) the initial stack frame setup for the entry point. And usually argv and environ/envp arrays simply hold pointers directly to this memory region, at least initially. On Linux /proc/$$/environ reads out this region, so it won't necessarily reflect a process' actual environment variables once a process starts changing them. [1] For both Linux and, at least historically, the BSDs.