I am getting the below error on arithmetic values
#!/bin/bash
n=0
line_count=9
line_count=$(line_count)/3
echo $line_count
exit 0
expected result is 3
[]$ ./test.sh
./test.sh: line 4: line_count: command not found
/3
[]$ more test.sh
-
Check the placement of your parantheses.schaiba– schaiba2017-02-16 12:34:55 +00:00Commented Feb 16, 2017 at 12:34
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2 Answers
To complement @Kusalananda's answer, in addition to the standard sh syntax:
line_count=$((line_count / 3))
In bash you can also use these syntaxes inherited from ksh (also work in zsh):
((line_count = line_count / 3))
((line_count /= 3))
let line_count/=3
typeset -i line_count; line_count=line_count/3
bash (and zsh) also support:
line_count=$[line_count/3]
For old pre-POSIX Bourne/Almquist sh:
line_count=`expr "$line_count" / 3`
answered Feb 16, 2017 at 12:51
Stéphane Chazelas
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Arithmetic expansion is done by bash and some other shells with $(( ... )), e.g.
line_count=$(( line_count/3 ))
With line_count=$(line_count)/3, you are assigning the output of the command line_count to the variable line_count, suffixed by /3.
This is why you get the error "line_count: command not found" and then the output /3.
Have a look at ShellCheck at https://www.shellcheck.net/
It is able to check you script for common issues. In this case, it won't help you with spotting that $(...) should have been $((...)) but that's because $(line_count) is perfectly legal shell code. It just does the wrong thing.
