I wanted to run the unix command in Julia as follows:
run(`TZ=UTC touch -t "YYMMDDhhmm" filename`)
but got an IOError, assuming that I am in a different time zone from UTC and wanted to set the timestamp of a file in UTC. The above works without TZ=UTC, but the timestamp is set according to my local time zone.
The Cmd literal is not spawning a shell, it spawns processes directly. Prepending environment variables like that is a feature of your shell, not of spawning a process. To influence environment variables of spawned processes, use addenv.