@FaheemMitha You can and they wont take it back now. I tried to modify it to work lol

@Jesse_b Bummer.

does anyone know where I can find documentation on shell tests?

duh nvm sorry I was looking at the old shell manual and there is a link at the top to the new one -.-

but I don't think they are valid shell tests

Why don't you think that?

test -n will always evaluate to true I believe

regardless of whether there is a string after it

-z seems to work though

What is the basis of that belief?

I can't find an implementation that does that

$ unset var
$ test -n $var && echo true
true

$ [ -n ] && echo true
true

now it is valid with the bash test sure

test -x returns true for every x

yes

Because it's not an operator expression

so how does -n work then?

how does it test for a zero length string

It's just an admittedly confusing application of test "$x" is-this-null

You give it a string to look at and it will

what is a zero length string other than nothing?

Compare test -n and test -n ""

@Jesse_b An absent argument is not the same as an empty argument

@MichaelHomer not quoting my variables >.> thanks

shame on me lol

With two arguments to test: "If $1 is a unary primary, exit true if the unary test is true, false if the unary test is false."

With one argument to test: "Exit true (0) if $1 is not null; otherwise, exit false."

Arguably it'd be nice if it didn't work that way, but making [ "$x" ] work for any x is important

Yea I almost always use bash tests, I'm writing up a demo on the different tests (over my head) so I wanted to show the differences between them

Thanks though I get what I was doing wrong :-)

I fully edited and narrowed my question, Please consider open it

Experienced with network monitoring tools? Which will you say is the simplest from these? Cacti, Check MK, Icinga, Nagios, NeDi, OpenNMS, Shinken, Vigilo NMS, Zabbix

Simplest == could inform me if a site is down and beside that, will have as few components as possible.

@JeffSchaller (related to your answer on that cat question) I was asked to debug what I presume must be a very old shell script today. It had things like if [ "``set -f; $echo $variable | sed 'sedscript'``" ]; then in it (yes, $echo was set to /usr/bin/echo, /bin/echo or just echo depending on which it found first). Presumably, it was written on a system where echo possibly even included the quotes in "$variable" in its output (original Bourne shell?).

(double backtick should be single backticks above. I never get the markup right with those)

@user9303970 as an aside from me, if you're not asking about NixOS, I would suggest using "nix or, since you're on the U&L site, dropping "Nix" altogether.

sigh asterisks are special. *nix maybe?

there we go.

@JeffSchaller No, the script used set -f inside a command substitution to be able to echo the value of a variable without quoting it, to sed for modification. Today we can use built-in and standard parameter substitutions for things like that.

I was debugging this code as I saw that answer from you, that's all.

@Kusalananda ahhhh, yes. Thanks for spelling it out; the caffeine clearly hasn't taken hold of me yet. It is not often that you see set -f, although I suppose it's encouraging to see someone trying to be careful.

@JeffSchaller, great minds etc. :P

@ilkkachu I saw other answers popping up, and kept checking to see who might be tackling the bigger problem of parsing ls ... guess I wasted too much time refreshing :) Well done!

shoot, and I didn't quote my variables! (ninja edit)