ksh: if statement negation and arithmetic evaluation

[support_billa]

Hello,

I use KSH  Version M-11/16/88f with HP-UX 11.31.

How can use in a "if statement" with a "function" the negation .

Only this works with ":"

if ( function "${parameter1}" )
then :
else
cmd1
cmd2
..
fi

i get an error when i use "!" to negate :

if ! ( function "${parameter1}" )
then

cmd1
fi

syntax error at line XXX : `(' unexpected

second question : when i want to check if the sum of two numbers is lower then another number ,

then i use this :

n1=10
n2=10

max_n=40

if [ $(( ${n1} + ${n2} )) -le ${max_n} ]
then
  echo ok
fi

i tested with input of this thread :

if statement negation and Arithmetic evaluation

[Dennis Handly · Accepted solution]

>How can use in a "if statement" with a "function" the negation .

You can't use ksh 88 with that "!".  You must use ksh 93 (dtksh) or the Posix shell.

>if ! ( function "${parameter1}" )

This works fine in the Posix shell, sh.

Also, you shouldn't be using those (...), that creates a subshell.

If you like some type of balanced punctuation, you can use:

if ! { function "${parameter1}"; } then

>when I want to check if the sum of two numbers is lower then another number,

Your code works, what was your question?

But it would look better if you switched to arithmetic expressions:

if (( n1 + n2 <= max_n )); then

>I tested with input of this thread :
if statement negation and Arithmetic evaluation

Your hyperlink isn't valid.  It is missing a ":" after "http".

You should be able to use Post Options > Edit Reply, to correct it.  (I fixed my copy.)

[support_billa]

hello,

thx a lot and i corrected it

regards