Its how you launch (execute) a new program. Such programs typically don’t have any interaction so the v and the e parts refer to the two ways you can control w

Its how you launch (execute) a new program. Such programs typically don’t have any interaction so the v and the e parts refer to the two ways you can control what the program does. v: a vector (list) of input parameters (aka arguments) e: an environment of key-value pairs The executed program can interpret these two in any way it wishes to, though there are many conventions that are followed (and bucked by the contrarians!) like using “-“ to prefix flags/options. This is in addition to any data sent to the program’s standard input — hence the original discussion about using pipes to send the output of one command to the input of another.