am trying to write a script that test that the load average which is taken from the uptime command's output to make sure it doesn't pass a certain limit. each time I execute the script, it complains about interger errors.
if (2 Replies)
hi, im trying to compare two variables in csh to put in an if statement, eg:
set a = $firstnum
set b = $secondnum
if ($a -ge $b) echo $a
But I get an error ("if: Expression syntax"). How can I make csh see my variables as integers?
thanks in advance! (5 Replies)
I'm trying to write an integer to a file using the write() function, but write() requires the parameter to be written to be a const void*.
How would I go about doing this?
also: using itoa() produces a " warning: implicit declaration of function 'itoa' " even though i have #included stdlib.h (2 Replies)
I am using gawk in a dos shell in windows xp and want to read a datafile and reformat it.
The datafile consists of columns of integers, floating point numbers and text strings. Each column is a fixed width and each column contains the same data type, eg all integers, all text.
I am looking for a... (0 Replies)
Wonderful evening to all of you!
My problem has to possible starting points.
Well, not really, but getting to either one is no problem at all.
So i got either a string in the format of "1920x1080" or simply the integers X = 1920 and Y = 1080.
When I am done, I would like to have an output... (5 Replies)
I'm trying to write a bash script to perform basic arithmetic operations but I want to run a comparison on the arguments first to check that they're a number greater than zero.
I want an error to pop up if the arguments args aren't >= 0 so I have:
if ! ]; then
echo "bad number: $1"
fi
... (14 Replies)
Hi,
I am working in bash in Mac OSX, I have following 'input.txt' file:
<INFO> HypoTestTool: >>> Done running HypoTestInverter on the workspace combined
<INFO> HypoTestTool: The computed upper limit is: 11 +/- 1.02651
<INFO> HypoTestTool: expected limit (median) 11
<INFO> HypoTestTool: ... (13 Replies)
Hy friends, I am newbie to bash scripting, can anyone explain how b=${a/23/BB} # Substitute "BB" for "23". this line converts "b" into string and and "d" into Integer. Thanks in advance (4 Replies)
Hi,
I'm totally new at this, so help will be appreciated.
I have a directory with a bunch of files in it. The files are named xinteger_yinteger_zinteger.vtk (eg, x3_y0_z-1.vtk). I want to read the filenames and then assign the integers to variables that I then can use in expressions. So, for... (6 Replies)
Hi,
I can't figure out what I'm missing. I'm running a query to see if there are any streams recording on my DVR before starting a scripted update. I'm guessing that it is viewing $VIDEO as a string instead of an int. I've tried everything I saw on google but it still comes back as $VIDEO is... (8 Replies)
Discussion started by: Rhysers
8 Replies
LEARN ABOUT ULTRIX
expr
expr(1) General Commands Manual expr(1)Name
expr - evaluate expressions
Syntax
expr arg...
Description
The arguments are taken as an expression. After evaluation, the result is written on the standard output. Each token of the expression is
a separate argument.
The operators and keywords are listed below. The list is in order of increasing precedence, with equal precedence operators grouped.
expr | expr Yields the first expr if it is neither null nor 0. Otherwise yields the second expr.
expr & expr Yields the first expr if neither expr is null or 0. Otherwise yields 0.
expr relop expr The relop is one of < <= = != >= > and yields 1 if the indicated comparison is true, '0' if false. The comparison is
numeric if both expr are integers, otherwise lexicographic.
expr + expr
expr - expr
Yields addition or subtraction of the arguments.
expr * expr
expr / expr
expr % expr
Yields multiplication, division, or remainder of the arguments.
expr : expr The matching operator compares the string first argument with the regular expression second argument; regular expres-
sion syntax is the same as that of The (...) pattern symbols can be used to select a portion of the first argument.
Otherwise, the matching operator yields the number of characters matched ('0' on failure).
( expr ) parentheses for grouping.
Examples
The first example adds 1 to the Shell variable a:
a=`expr $a + 1`
The second example finds the file name part (least significant part) of the pathname stored in variable a,
expr $a : '.*/(.*)' '|' $a
Note the quoted Shell metacharacters.
Diagnostics
The command returns the following exit codes:
0 The expression is neither null nor '0'.
1 The expression is null or '0'.
2 The expression is invalid.
See Alsoed(1), sh(1), test(1)expr(1)