• sum
  • awk
  • datamash
  • bc
  • jq
  • $(())
• sum from file
• advanced computing
  • logarithm
  • power
  • square
  • decimal to binary
  • binary <> decimal <> hexadecimal

[!NOTE|label:references:]

• Bash 的算术运算
• Linux 中bc命令实现自然对数、指数运算、自然指数、平方根的运算
• bc to Perform Advanced Arithmetic Operations in BASH
• Using vim as calculator

sum

[!INFO|label:references:]

• Shell command to sum integers, one per line?
• Summing a List of Numbers

awk

$ seq 10 | awk '{s+=$1} END {print s}'
55

# or
$ awk 'BEGIN{print '"1+2+3"'}'
6

file sizes

$ ls -l
total 12
-rw-r--r--  1 marslo staff 3480 Dec 21 21:21 README.md
-rw-r--r--  1 marslo staff 7516 Dec 21 21:21 SUMMARY.md
drwxr-xr-x  7 marslo staff  224 Sep 19 19:52 artifactory
drwxr-xr-x 15 marslo staff  480 Dec 21 21:19 cheatsheet
drwxr-xr-x 12 marslo staff  384 Aug 17 21:11 devops
drwxr-xr-x  9 marslo staff  288 Sep 29 17:31 jenkins
drwxr-xr-x 10 marslo staff  320 Sep 19 19:52 linux
drwxr-xr-x  9 marslo staff  288 Sep 19 19:52 osx
drwxr-xr-x  6 marslo staff  192 Aug 17 21:11 programming
drwxr-xr-x 27 marslo staff  864 Aug 17 22:10 screenshot
drwxr-xr-x  7 marslo staff  224 Oct 11 19:41 tools
drwxr-xr-x  8 marslo staff  256 Aug 30 16:39 vim
drwxr-xr-x  5 marslo staff  160 Aug 17 21:11 virtualization

$ ls -l | awk '{sum += $5} END {print sum}'
14676

datamash

[!TIP|label:reference:]

• Shell command to sum integers, one per line?

$ seq 10 | datamash sum 1
55

bc

• paste + bc

  $ seq 10 | paste -sd+ -
  1+2+3+4+5+6+7+8+9+10
  
  $ seq 10 | paste -sd+ - | bc
  55
  

• xargs + bc

  $ seq 10 | xargs printf "- - %s" | xargs | bc
  55
  

• sed + bc

  $ seq 10 | sed 's/^/.+/' | bc
  1
  3
  6
  10
  15
  21
  28
  36
  45
  55
  

jq

$ seq 10 | jq -s 'add'
55

$(())

$ f=$(seq 10)
$ echo $(( ${f//$'\n'/+} ))
55

# or
$ echo $(( $(seq 10 | tr "\n" "+") 0 ))
55
# or from file
$ echo $(( $( tr "\n" "+"  < /tmp/test) 0 ))

sum from file

[!NOTE|label:sample file:]

$ cat numbers.txt
73.27
218.38
14.15
9.18
16.60

• How can I quickly sum all numbers in a file?

• awk

  
  $ awk '{ sum += $1 } END { print sum }' numbers.txt
  331.58
  

• paste && bc

  $ paste -sd+ numbers.txt
  73.27+218.38+14.15+9.18+16.60
  
  $ paste -sd+ numbers.txt | bc
  331.58
  

  • Σn where 1<=n<=100000

    $ seq 100000 | paste -sd+ | bc -l
    5000050000
    

• jq

  $ paste -sd' ' numbers.txt | jq -s add
  331.58
  

advanced computing

[!NOTE|label:references:]

• How to calculate the log of a number using bc?
• 指数与对数
• n次方根

logarithm

• bc

  $ bc -l <<< 'l(9)/l(3)'
  2.00000000000000000000
  

  • 🫠

    $ bc -l <<< 'l(512)/l(2)'
    9.00000000000000000008
    

• awk

  $ echo 512 | awk '{print log($1)/log(2)}'
  9
  

power

• bc

  $ bc <<< '2^3'
  8
  

• $(())

  $ echo $(( 2**8 ))
  256
  

square

$ bc -l <<< 'sqrt(2)'
1.41421356237309504880

$ bc <<< 'sqrt(2)'
1

decimal to binary

[!NOTE|label:references:]

• Prevent bc from auto truncating leading zeros when converting from hex to binary
• How to make bc output a desired number of base-2 binary digits

• bc

  $ bc <<< 'obase=2;15'
  1111
  
  $ bc -l <<< 'obase=2;0;0;15;255' | xargs
  0 0 1111 11111111
  
  $ bc -l <<< 'obase=2;0;0;15;255' | awk '{ printf "%08d\n", $0 }' | xargs
  00000000 00000000 00001111 11111111
  
  $ printf "%08d\n" $(echo "obase=2; 0;0;15;255" | bc) | xargs
  00000000 00000000 00001111 11111111
  
  $ bc <<< 'obase=2; 0;0;15;255' | numfmt --format=%08f | xargs
  00000000 00000000 00001111 11111111
  

binary <> decimal <> hexadecimal

[!NOTE]

• obase : [o]utput base
• ibase : [i]utput base

# bin -> dec
$ bc <<< 'ibase=2;11111111;11111111;11000000;00000000' | paste -sd. -
255.255.192.0

# bin -> hex
$ bc <<< 'obase=16;ibase=2;11111111;11111111;11000000;00000000' | awk '{ printf "%04s\n", $1 }' | paste -sd. -
00FF.00FF.00C0.0000

# dec -> bin
$ bc <<< 'ibase=10;obase=2;255;255;240;0' | numfmt --format %08f | paste -sd' ' -
11111111 11111111 11110000 00000000

# dec -> hex
$ bc <<< 'ibase=10;obase=16;255;255;240;0' | awk '{ printf "%04s\n", $1 }' | paste -sd. -
00FF.00FF.00F0.0000

# hex -> bin
$ bc <<< 'ibase=16;obase=2;FF;FF;EE;0A' | numfmt --format %08f | paste -sd' ' -
11111111 11111111 11101110 00001010

# hex -> dec
$ bc <<< 'ibase=16;FF;FF;EE;0A' | paste -sd. -
255.255.238.10