Rounding a number in awk

Question

I’m trying to find a way to round up a few numbers.

The topic I found: https://stackoverflow.com/questions/2395284/round-a-divided-number-in-bash

I am using the following command in my bash script..

free -h | gawk '/Mem:/{print $2}' | awk 'FNR == 1 {print $1 "B"}')

The following code will show me how much in total Memory i have installed. Currently, im getting 3.7GB. The problem is, i need this to be rounded up to 4GB.

I have a script that requests my machine a bunch of info and will echo it all out. (Prolly should use something different but haven't tried anything else yet as this is one of my projects that i am working on.

memory=$(free -h | gawk '/Mem:/{print $2}' | awk 'FNR == 1 {print $1 "B"}')

echo $memory

Right now it echo's out 3.7GB as mentioned below. I'v tried it different ways but can't seem to get it to 4GB.

This doesn’t address your rounding question, but see [this question](https://unix.stackexchange.com/q/421193/86440) to correctly determine the amount of installed memory. — Stephen Kitt, Mar 21 '18 at 11:58
Sadly can't install new software. I need to use the ones that come with Debian. — TheSebM8, Mar 21 '18 at 12:20
`dmidecode` is priority important so it should be present on most Debian systems. You can’t guarantee you’ll get the correct result from `free` (especially `free -h` — *e.g.* on systems with 10 GiB of RAM or more, it will lose a full gibibyte). — Stephen Kitt, Mar 21 '18 at 12:30

Stéphane Chazelas · Accepted Answer · 2018-03-21T13:00:10.573

4

You could do something like:

memory=$(
  LC_ALL=C free -h | awk '
    /^Mem/ {
      suffix = $2
      sub(/[0-9.]*/, "", suffix)
      printf "%.0f%sB\n", $2, suffix
    }'
)

(LC_ALL=C to make sure the numbers are printed using the . decimal radix (3.7G would be output as 3,7G in locales using comma as the decimal radix)).

On GNU/Linux systems, you can also do:

memory=$(
  awk '/^MemTotal/{print $2*1024}' < /proc/meminfo |
    numfmt --to=iec --format=%0f --suffix=B
)

Or:

memory=$(
  free -h | awk '/^Mem/{print $2}' |
    numfmt --from=iec --to=iec --format=%0f --suffix=B
)

(that one coping with locales where the decimal radix is not .).

Note that free on Linux reports that MemTotal field of /proc/meminfo. As per proc(5), that's the total usable RAM (i.e., physical RAM minus a few reserved bits and the kernel binary code). For the physical RAM, and for PCs, as pointed out by @StephenKit, you may be better off using dmidecode to get the information from the BIOS, though you'd need superuser privileges for that:

physical_memory=$(
  sudo dmidecode -t memory |
    awk '$1 == "Size:" && $2 ~ /^[0-9]+$/ {print $2$3}' |
    numfmt --from=iec --suffix=B |
    awk '{total += $1}; END {print total}' |
    numfmt --to=iec --suffix=B --format=%0f
)

edited Mar 21 '18 at 13:00

answered Mar 21 '18 at 12:15

Stéphane Chazelas

522,931
91
1,010
1,501

Sadly this still gives me 3.7GB – TheSebM8 Mar 21 '18 at 12:19
@TheSebM8. How come? Does your `awk` print 3.7 for `awk 'BEGIN{printf "%.0f\n", 3.7}'`? – Stéphane Chazelas Mar 21 '18 at 12:20
@TheSebM8 You probably made a typo in that case. – Kusalananda Mar 21 '18 at 12:21
@kusalanda no, i did notmake any typos. I copied what Stephane gave me. StéphaneChazelas that one does round it to 4. – TheSebM8 Mar 21 '18 at 12:23
@TheSebM8, is it possible that you get `3,7G` instead of `3.7` (see edit)? Otherwise, like Kusalananda, I can't explain it other than with a typo. – Stéphane Chazelas Mar 21 '18 at 12:29
@StéphaneChazelas All of the commands you gave worked perfectly. Thank you! – TheSebM8 Mar 21 '18 at 12:33
@StephenKitt, under what condition would they underestimate by 1 GiB (other than 1.1T rounded to 1T?) – Stéphane Chazelas Mar 21 '18 at 12:35
Won't be having any server with over 1 TB RAM, so i'd say this works good :P – TheSebM8 Mar 21 '18 at 12:37
Basically there’s no fool-proof way to go from `MemTotal` to the amount of memory really installed. You need something like `dmidecode` instead. – Stephen Kitt Mar 21 '18 at 12:39
@StéphaneChazelas how would you put your LC_ALL command into a bash script so if you " printf $memory it would print ut the result? – TheSebM8 Mar 21 '18 at 12:41
@TheSebM8, see edit – Stéphane Chazelas Mar 21 '18 at 13:00

score 2 · Answer 2 · answered Mar 21 '18 at 12:12

2

$ echo "3.7" | awk '{printf("%d\n",$1 + 0.5)}'
4

answered Mar 21 '18 at 12:12

Mikhail Zakharov

298
2
9

Can't use it like this. I need a way that does it for every different machine. – TheSebM8 Mar 21 '18 at 12:14

score 2 · Answer 3 · edited Aug 01 '18 at 18:34

2

If you want to round to 2 decimal, here are some simple examples:

echo "12345.12345" | nawk '{printf ("%.2f\n", $1+0.005)}'
echo "12345.345" | nawk '{printf ("%.2f\n", $1+0.005)}'

edited Aug 01 '18 at 18:34

jesse_b

35,934
12
91
140

answered Aug 01 '18 at 18:27

Wenzhong Mo

21
1

Rounding a number in awk

3 Answers3