11–20 of 68 posts
Now do [ ... ] and [[ ... ]] I'm still not sure when to use one or the other. I use double brackets by default until something doesn't work.
I usually default to [ ... ] unless I need features that double brackets provide.
if "[" "$foo" "==" "bar" "]"; then ...Now do [ ... ] and [[ ... ]] I'm still not sure when to use one or the other. I use double brackets by default until something doesn't work.
[[...]] is non-portable and has an extremely quirky corner case with variable expansion in arithmetic contexts, what's not to love?
I personally use ((...)) for arithmetic tests and [[...]] for all other tests as I just target new versions of BASH and don't care much about POSIX compatibility.
Now do [ ... ] and [[ ... ]] I'm still not sure when to use one or the other. I use double brackets by default until something doesn't work.
> When I was a young, green, university student, I was forced to use test(1) as the only true way to do testing in shell scripting. […] Yeah, I was also forced to not use semicolons as they were evil (according to my professor, any comment unneeded!). The author’s professor clearly went overboard, but doesn’t this entire anecdote demonstrate the value of teaching it this way? Having green students call the `test` bin…
The ultimately sad part was the professor in a Sun OS machine. In a corner with no where to go, giving demerits because his bash was older than he realized. Reminds me of my college professor that claimed you don’t have to close HTML tags (some you absolutely do) and I proved that you do. Not all of them, but most of them. (Netscape Navigator Days)
Now do [ ... ] and [[ ... ]] I'm still not sure when to use one or the other. I use double brackets by default until something doesn't work.
Use ((...)) for arithmetic tests and [[...]] for other tests. [...] is for POSIX compatibility and not as useful as [[...]] though I don't remember the specifics.
Now do [ ... ] and [[ ... ]] I'm still not sure when to use one or the other. I use double brackets by default until something doesn't work.
[[...]] is non-portable and has an extremely quirky corner case with variable expansion in arithmetic contexts, what's not to love?
> When I was a young, green, university student, I was forced to use test(1) as the only true way to do testing in shell scripting. […] Yeah, I was also forced to not use semicolons as they were evil (according to my professor, any comment unneeded!). The author’s professor clearly went overboard, but doesn’t this entire anecdote demonstrate the value of teaching it this way? Having green students call the `test` bin…
Hmm. What if we replaced the whole of bash with the contents of /bin?
I do think it makes sense to have beginners use `sh` instead of `bash`.