How to loop through a range of decimal numbers in bash?

Question

I'd like to generate a sequence of equally spaced decimal numbers.

For example, I want to echo all numbers between 3.0 and 4.5, with step 0.1. I tried $ for i {3.0..4.5..0.1}; do echo $i; done, but this gives an error.

I also tried $ for i in $(seq 3.0 4.5 0.1); do echo $i; done but nothing happens.

Bash doesn't do floating point numbers. You're best off switching to a different scripting language. — John Kugelman
– John Kugelman, Commented Jun 10, 2015 at 22:51
Is there a command to replace seq that can generate that list so I can use it? — izxle
– izxle, Commented Jun 10, 2015 at 22:59

Ole Tange · Accepted Answer · 2015-06-22 09:48:06Z

25

I also tried $ for i in $(seq 3.0 4.5 0.1); do echo $i; done but nothing happens.

The order is wrong:

$ for i in $(seq 3.0 0.1 4.5); do echo $i; done

answered Jun 22, 2015 at 9:48

Ole Tange

34.1k9 gold badges93 silver badges111 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

izxle Over a year ago

Wow, thanks this works great. Much easier to read than the other methods.

drpetermolnar · Accepted Answer · 2015-06-10 23:00:47Z

5

If you're looking for a loop from 3.5 to 4.5 in 0.1 steps this would work

for x in {35..45}; do y=`bc <<< "scale=1; $x/10"` echo $y done

The same with 0.01 steps

for x in {350..450}; do y=`bc <<< "scale=2; $x/100"` echo $y done

answered Jun 10, 2015 at 23:00

drpetermolnar

1794 bronze badges

3 Comments

izxle Over a year ago

Thanks, this works. Is bc compulsory for the division?

izxle Over a year ago

Just googled it, now I'm using for x in {30..45}; do y=$(dc <<< "1k $x 10/p"); echo $y; done.

drpetermolnar Over a year ago

Yeah, either one works. bash only support integer arithmetic. Therefore, one always needs to use another program...

bmscomp · Accepted Answer · 2015-06-10 22:55:06Z

-2

 for i in {3.0,4.5,0.1}; do echo $i; done

answered Jun 10, 2015 at 22:55

bmscomp

7971 gold badge11 silver badges22 bronze badges

5 Comments

izxle Over a year ago

No, that only prints three lines 3.0, 4.5 and 0.1.

bmscomp Over a year ago

What do you want to print ??

izxle Over a year ago

A range of decimal numbers, e.g. 3.0 3.1 3.2 3.3 ... 4.5

sancho.s ReinstateMonicaCellio Over a year ago

@izxle - The original question was prone to misunderstandings. The syntax shown here is useful for what it was meant to.

Charles Duffy Over a year ago

What this syntax is "meant to do", however, has no reasonable relationship with "loop[ing] through a range of decimal numbers".

Collectives™ on Stack Overflow

How to loop through a range of decimal numbers in bash?

3 Answers 3

1 Comment

3 Comments

5 Comments

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

3 Comments

5 Comments

Related