Round a divided number in Bash

Question

How would I round the result from two divided numbers  e g   3 2   As when I do   testOne    3 2      testOne contains  1  when it should have rounded up to  2  as the answer from 3 2 1 5

User · Answer

If the decimal separator is comma  eg   LC NUMERIC fr FR UTF-8  see here      printf    0f    echo  scale 2 3 2    bc   bash  printf  1 50  nombre non valable 0   Substitution is needed for ghostdog74 solution      printf    0f    echo  scale 2 3 2    bc   sed  s          2   or    printf    0f    echo  scale 2 3 2    bc   tr          2

User · Answer

Given a floating point value  we can round it trivially with printf     round  1 to  2 decimal places round         printf      2 -0 f    1      Then     do some math  bc style math         echo        bc -l      echo  Pi  to five decimal places  is   round   math  4 a 1    5   Pi  to five decimal places  is 3 14159   Or  to use the original request     echo  3 2  rounded to the nearest integer  is   round   math  3 2   0   3 2  rounded to the nearest integer  is 2

User · Answer

I think this should be enough     echo  3 2    bc

User · Answer

To do rounding up in truncating arithmetic  simply add  denom-1  to the numerator   Example  rounding down   N 2 M 5 K 16   Example  rounding up    N 1  2  M 4  5  K 15  16   To do round-to-nearest  add  denom 2  to the numerator  halves will round up     N 1  2  M 2  5  K 8  16

User · Answer

Following worked for me       bin bash function float     bc  lt  lt  EOF num    1  base   num   1  if    num - base    10   gt  1       base    1  print base  EOF echo       float 3 2

User · Answer

Another solution is to do the division within a python command   For example     numerator 90   denominator 7   python -c  print  round   numerator  0     denominator  0      Seems less archaic to me than using awk

User · Answer

bash will not give you correct result of 3 2 since it doesn t do floating pt maths  you can use tools like awk    awk   BEGIN   rounded   sprintf    0f   3 2   print rounded    2   or  bc    printf    0f    echo  scale 2 3 2    bc  2

User · Answer

Good Solution is to get Nearest Round Number is   var 2 5 echo  var   awk   print int  1 0 5      Logic is simple if the var decimal value is less then  5 then closest value taken is integer value   Well if decimal value is more than  5 then next integer value gets added and since awk then takes only integer part  Issue solved

User · Answer

To round up you can use modulus   The second part of the equation will add to True if there s a remainder   True   1  False   0   ex  3 2  answer     3   2     3   2  gt  0    echo  answer 2   ex  100   2  answer     100   2     100   2  gt  0    echo  answer 50   ex  100   3  answer     100   3     100   3  gt  0    echo  answer 34

User · Answer

If you have integer division of positive numbers which rounds toward zero  then you can add one less than the divisor to the dividend to make it round up   That is to say  replace X   Y with  X   Y - 1    Y   Proof    Case 1  X   k   Y  X is integer multiple of Y    In this case  we have  k   Y   Y - 1    Y  which splits into  k   Y    Y    Y - 1    Y  The  Y - 1  Y part rounds to zero  and we are left with a quotient of k    This is exactly what we want  when the inputs are divisible  we want the adjusted calculation to still produce the correct exact quotient  Case 2  X   k   Y   m where 0  lt  m  lt  Y  X is not a multiple of Y    In this case we have a numerator of k   Y   m   Y - 1  or k   Y   Y   m - 1  and we can write the division out as  k   Y  Y   Y Y    m - 1  Y   Since 0  lt  m  lt  Y  0  lt   m - 1  lt  Y - 1  and so the last term  m - 1  Y goes to zero  We are left with  k   Y  Y   Y Y which work out to k   1   This shows that the behavior rounds up  If we have an X which is a k multiple of Y  if we add just 1 to it  the division rounds up to k   1    But this rounding is extremely opposite  all inexact divisions go away from zero  How about something in between   That can be achieved by  priming  the numerator with Y 2  Instead of X Y  calculate  X Y 2  Y  Instead of proof  let s go empirical on this one     round    gt     gt    echo      1    2 2     2    gt      round 4 10 0   round 5 10 1   round 6 10 1   round 9 10 1   round 10 10 1   round 14 10 1   round 15 10 2   Whenever the divisor is an even  positive number  if the numerator is congruent to half that number  it rounds up  and rounds down if it is one less than that   For instance  round 6 12 goes to 1  as do all values which are equal to 6  modulo 12  like 18  which goes to 2  and so on   round 5 12 goes down to 0   For odd numbers  the behavior is correct  None of the exact rational numbers are midway between two consecutive multiples  For instance  with a denominator of 11 we have 5 11  lt  5 5 11  exact middle   lt  6 11  and round 5 11 rounds down  whereas round 6 11 rounds up

[linux] Round a divided number in Bash

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