Roberto C. Sanchez wrote:
On Thu, Oct 12, 2006 at 08:51:29PM -0400, José Alburquerque wrote:I guess I could do that, it's just that I use certain commands almost "instinctively" and sometimes I forget. A lot of times I'm running certain processes one after the other in several shells. It is after I've run them that I realize that it would have been nice to "time" some of them.I suppose I could just be more attentive as to which commands I'd like to "time". I'll keep what you say in mind. :-)If it is always the same commands, then consider setting them to use the time command as an alias. For example, if you always want to know how long a dd took, then use something like `alias dd='/usr/bin/time /usr/bin/dd'`. Of course, you will need to use dd and not /usr/bin/dd to get the benefit. Additionally, if you set your alias like this: `alias dd='/usr/bin/time dd'`, then it will recurse and bad things will happen. Trust me on this :-) I once did `alias mutt='LANG= mutt'` and when I executed it, I had to reboot the machine to get it to quit. Regards, -Roberto
I will agree that, if you only have a few commands that you regularly want timed, then an alias is probably the easiest way to do it.
I have the following alias: alias pr='pr -F -l 59', and it works just fine, no recursion at all. I just checked 'man bash' and this is what it says:
ALIASESAliases allow a string to be substituted for a word when it is used as the first word of a simple command. The shell maintains a list of aliases that may be set and unset with the alias and unalias builtin commands (see SHELL BUILTIN COMMANDS below). The first word of each command, if unquoted, is checked to see if it has an alias. If so, that word is replaced by the text of the alias. The alias name and the replacement text may contain any valid shell input, including the metacharacters listed above, with the exception that the alias name may not contain =. The first word of the replacement text is tested for aliases, but a word that is identical to an alias being expanded is not expanded a second time. This means that one may alias ls to ls -F, for instance, and bash does not try to recursively expand the replacement text. If the last character of the alias value is a blank, then the next command word following the alias is also checked for alias expan-
sion.
Aliases are created and listed with the alias command, and
removed with
the unalias command.
So I'm don't see what could have caused the recursion Roberto mentioned,
unless that was some time ago and the behavior of 'alias' has changed.
At any rate, it should be safe to use the command name as an alias and
run time from within the replacement text, as in:
alias command='time command' In fact, I just tested alias ls='time ls' and it worked just fine. -- Marc Shapiro No boom today. Boom tomorrow. There's always a boom tomorrow. What?! Look, somebody's got to have some damn perspective around here. Boom. Sooner or later ... boom! - Susan Ivanova: B5 - Grail