Chet Ramey wrote: > b...@feusi.co wrote: > > The thing I noticed is that when setting a variable and then running the > > command "time", bash reports "command not found". For example, the > > command: > > > > TEST=1 time ls > > > > Results in "bash: time: command not found"
That would work if you installed the GNU time package. https://www.gnu.org/software/time/ And it would produce the portable output format in both cases with the time -p option, which is available both in the internal time and the external GNU time command. Otherwise GNU time has its own unique and different default output format. $ TEST=1 time -p sleep 1 real 1.00 user 0.00 sys 0.00 But regardless of the external standalone time program... Order when using the internal time here matters. Since 'time' is special it should always be first. Put any variables to be set on the line before the command by putting it before the command but after the 'time' word. $ time TEST=1 sleep 1 real 0m1.003s user 0m0.000s sys 0m0.000s > You don't have a command named `time' in a directory in your $PATH. Well... *They* don't have a time program in PATH. But they could have if they installed it. And many people do. :-) > Bash doesn't have a `time' builtin; it has a `time' reserved word. > Preceding `time' with a variable assignment removes its special meaning > and causes it to not be recognized as a reserved word. I might also mention that the bash 'time' needs this special status because it times the entire pipeline. $ time sleep 1 | sleep 2 real 0m2.004s user 0m0.003s sys 0m0.002s Therefore conversely if someone is using the external time it might give them an unexpected result. Since the external time will not know anything about a pipeline. So this might catch people off guard too. $ TEST=foo time -p sleep 1 | sleep 2 real 1.00 user 0.00 sys 0.00 When used it is best to always put 'time' first on the command line, variables second, and commands after that. Order matters[1]. Bob [1] OT: In English the order also matters and it is always opinion, size, age, shape, color, origin, material, purpose, noun. Using any other order and it sounds really odd! Reference "The Elements Of Eloquence: How To Turn The Perfect English Phrase." by Mark Forsyth. http://www.npr.org/2016/09/08/493157931/bbc-editor-highlights-often-overlooked-english-language-rule
