Multiple arithmetic operation in awk - shell

Question

I have this awk function to do speed conversion.
function hum(x) {
split( "B/s KB/s MB/s GB/s TB/s", v); s=1
while( x>1000 ){ x/=1000; s++ }
printf( "%0.2f %s" , x , v[s] )
}
hum($1)
It works great if used standalone.
$ awk -f /tmp/test.awk <<< 1000000
1000.00 KB/s
$ awk -f /tmp/test.awk <<< 100000000
100.00 MB/s
Now, I want to convert bytes number to bit, to do that I need to multiple the number/input first by 8. I tried to modify the function a bit.
function hum(x) {
split( "B/s KB/s MB/s GB/s TB/s", v); s=1
while( x>1000 ){ res = x * 8 / 1000; s++ }
printf( "%0.2f %s\n" , res , v[s] )
}
hum($1)
But it hangs when I tried to execute it, I had to Ctrl-C to cancel the operation. Any idea what's wrong ?

Answer 1

Now, I want to convert bytes number to bit, to do that I need to multiple the number/input first by 8.
Then multiply the input value by 8 just once:
function hum(x) {
split("b/s Kb/s Mb/s Gb/s Tb/s", v); s=1
x *= 8
while(x > 1000) {x /= 1000; s++}
printf("%0.2f %s\n", x, v[s])
}
hum($1)

Answer 2

Instead of a loop, let's use log():
$ cat program.awk
function hum2(x, v,p) {
split( "b/s kb/s Mb/s Gb/s Tb/s", v) # remember to B -> b
x*=8 # to bits conversion
p=int(log(x)/log(1000)) # figure v slot
return sprintf("%0.2f %s" , x/1000^p , v[p+1] ) # p+1 due to 1 basedness
}
{
print $1,hum2($1) # input bytes, output bits
}
Take it for a spin:
$ for (( i=1 ; i<=10**14 ; i=i*10 )) ; do echo $i ; done | awk -f program.awk
Output:
1 8.00 b/s
10 80.00 b/s
100 800.00 b/s
1000 8.00 kb/s
10000 80.00 kb/s
100000 800.00 kb/s
1000000 8.00 Mb/s
10000000 80.00 Mb/s
100000000 800.00 Mb/s
1000000000 8.00 Gb/s
10000000000 80.00 Gb/s
100000000000 800.00 Gb/s
1000000000000 8.00 Tb/s
10000000000000 80.00 Tb/s
100000000000000 800.00 Tb/s

Answer 3

I wrote this one a while back that might not be exactly what you need but should be easily adaptable -
a function that takes in # of bytes as mandatory 1st parameter,
with optional 2nd param for calculating powers of 1000 instead of 1024
enter M m or 10 for 1000,
anything else, including blank, defaults to 1024
and auto formats it in the most logical range for human readability,
spanning all the way from kilo(kibi)-bit/s,
to YOTTA(yobi)-bit/s
*** extra credit for anyone who can figure out what's common among that list of numbers in my sample below.
——————————————————————— ———————————————————————
mawk/gawk '
function bytesformat(_, _______, __, ___, ____, _____, ______)
{
_____=__=(____^=___*=((____=___+=___^="")/___)+___+___)
___/=___
sub("^0+","",_)
____=_____-=substr(_____,index(_____,index(_____,!__)))*\
(_______ ~ "^(10|[Mm])$")
_______=length((____)____)
if ((____*__)<(_______*_)) {
do {
____ *= _____
++___
} while ((____*__)<(_______*_))
}
__=_
sub("(...)+$", ",&", __)
gsub("[^#-.][^#-.][^#-.]", "&,", __)
gsub("[,]*$|^[,]+", "", __)
sub("^[.]", "0&", __)
return \
sprintf(" %10.4f %sb/s (%42s byte%s) ",
_==""?+_:_/(_____^___)*_______,
substr("KMGTPEZY",___,___~___),
__==""?+__:__, (_~_)<_?"s":" ")
} { printf("%35s bytes ::: %s\n",
$1,
bytesformat($1, 10)) }'
6841 bytes ::: 54.7280 Kb/s ( 6,841 bytes)
15053 bytes ::: 120.4240 Kb/s ( 15,053 bytes)
23677 bytes ::: 189.4160 Kb/s ( 23,677 bytes)
32839 bytes ::: 262.7120 Kb/s ( 32,839 bytes)
42293 bytes ::: 338.3440 Kb/s ( 42,293 bytes)
52183 bytes ::: 417.4640 Kb/s ( 52,183 bytes)
62233 bytes ::: 497.8640 Kb/s ( 62,233 bytes)
72733 bytes ::: 581.8640 Kb/s ( 72,733 bytes)
83269 bytes ::: 666.1520 Kb/s ( 83,269 bytes)
138641 bytes ::: 1.1091 Mb/s ( 138,641 bytes)
149767 bytes ::: 1.1981 Mb/s ( 149,767 bytes)
162011 bytes ::: 1.2961 Mb/s ( 162,011 bytes)
174221 bytes ::: 1.3938 Mb/s ( 174,221 bytes)
186343 bytes ::: 1.4907 Mb/s ( 186,343 bytes)
199181 bytes ::: 1.5934 Mb/s ( 199,181 bytes)
211559 bytes ::: 1.6925 Mb/s ( 211,559 bytes)
224449 bytes ::: 1.7956 Mb/s ( 224,449 bytes)
237733 bytes ::: 1.9019 Mb/s ( 237,733 bytes)
128260807 bytes ::: 1.0261 Gb/s ( 128,260,807 bytes)
128565049 bytes ::: 1.0285 Gb/s ( 128,565,049 bytes)
128932561 bytes ::: 1.0315 Gb/s ( 128,932,561 bytes)
129304523 bytes ::: 1.0344 Gb/s ( 129,304,523 bytes)
129765859 bytes ::: 1.0381 Gb/s ( 129,765,859 bytes)
130111459 bytes ::: 1.0409 Gb/s ( 130,111,459 bytes)
130533133 bytes ::: 1.0443 Gb/s ( 130,533,133 bytes)
131012801 bytes ::: 1.0481 Gb/s ( 131,012,801 bytes)
131305043 bytes ::: 1.0504 Gb/s ( 131,305,043 bytes)
128004093619 bytes ::: 1.0240 Tb/s ( 128,004,093,619 bytes)
128026268633 bytes ::: 1.0242 Tb/s ( 128,026,268,633 bytes)
128056111093 bytes ::: 1.0244 Tb/s ( 128,056,111,093 bytes)
128071706179 bytes ::: 1.0246 Tb/s ( 128,071,706,179 bytes)
128082430067 bytes ::: 1.0247 Tb/s ( 128,082,430,067 bytes)
128102475287 bytes ::: 1.0248 Tb/s ( 128,102,475,287 bytes)
128115312811 bytes ::: 1.0249 Tb/s ( 128,115,312,811 bytes)
128157555781 bytes ::: 1.0253 Tb/s ( 128,157,555,781 bytes)
128175556181 bytes ::: 1.0254 Tb/s ( 128,175,556,181 bytes)
128004004377827 bytes ::: 1.0240 Pb/s ( 128,004,004,377,827 bytes)
128040044659991 bytes ::: 1.0243 Pb/s ( 128,040,044,659,991 bytes)
128074066014953 bytes ::: 1.0246 Pb/s ( 128,074,066,014,953 bytes)
128127783733093 bytes ::: 1.0250 Pb/s ( 128,127,783,733,093 bytes)
128177777757611 bytes ::: 1.0254 Pb/s ( 128,177,777,757,611 bytes)
128200131001829 bytes ::: 1.0256 Pb/s ( 128,200,131,001,829 bytes)
128221782218423 bytes ::: 1.0258 Pb/s ( 128,221,782,218,423 bytes)
128237784424429 bytes ::: 1.0259 Pb/s ( 128,237,784,424,429 bytes)
128262808216561 bytes ::: 1.0261 Pb/s ( 128,262,808,216,561 bytes)
128055360778053559 bytes ::: 1.0244 Eb/s ( 128,055,360,778,053,559 bytes)
128082834342828077 bytes ::: 1.0247 Eb/s ( 128,082,834,342,828,077 bytes)
128112814740831073 bytes ::: 1.0249 Eb/s ( 128,112,814,740,831,073 bytes)
128172605482718161 bytes ::: 1.0254 Eb/s ( 128,172,605,482,718,161 bytes)
128203333333333399 bytes ::: 1.0256 Eb/s ( 128,203,333,333,333,399 bytes)
128240343634404269 bytes ::: 1.0259 Eb/s ( 128,240,343,634,404,269 bytes)
128272818280928081 bytes ::: 1.0262 Eb/s ( 128,272,818,280,928,081 bytes)
128282816070718271 bytes ::: 1.0263 Eb/s ( 128,282,816,070,718,271 bytes)
128289494449498271 bytes ::: 1.0263 Eb/s ( 128,289,494,449,498,271 bytes)
128030578058078030329 bytes ::: 1.0242 Zb/s ( 128,030,578,058,078,030,329 bytes)
128172161171772727271 bytes ::: 1.0254 Zb/s ( 128,172,161,171,772,727,271 bytes)
128234814212823481421 bytes ::: 1.0259 Zb/s ( 128,234,814,212,823,481,421 bytes)
128282727262616060507 bytes ::: 1.0263 Zb/s ( 128,282,727,262,616,060,507 bytes)
128286164949865319531 bytes ::: 1.0263 Zb/s ( 128,286,164,949,865,319,531 bytes)
128372737272827373721 bytes ::: 1.0270 Zb/s ( 128,372,737,272,827,373,721 bytes)
128393838393839382839 bytes ::: 1.0272 Zb/s ( 128,393,838,393,839,382,839 bytes)
128505500051850550037 bytes ::: 1.0280 Zb/s ( 128,505,500,051,850,550,037 bytes)
128669659758768758857 bytes ::: 1.0294 Zb/s ( 128,669,659,758,768,758,857 bytes)
130000000000093999992023 bytes ::: 1.0400 Yb/s ( 130,000,000,000,093,999,992,023 bytes)
131111111311113111311131 bytes ::: 1.0489 Yb/s ( 131,111,111,311,113,111,311,131 bytes)
131111153353153531553111 bytes ::: 1.0489 Yb/s ( 131,111,153,353,153,531,553,111 bytes)
131111531315333335313531 bytes ::: 1.0489 Yb/s ( 131,111,531,315,333,335,313,531 bytes)
131113133333311333331111 bytes ::: 1.0489 Yb/s ( 131,113,133,333,311,333,331,111 bytes)
131113551355135511111111 bytes ::: 1.0489 Yb/s ( 131,113,551,355,135,511,111,111 bytes)
131131113131113131131111 bytes ::: 1.0490 Yb/s ( 131,131,113,131,113,131,131,111 bytes)
131131331133111331313111 bytes ::: 1.0491 Yb/s ( 131,131,331,133,111,331,313,111 bytes)
131133133131333313331311 bytes ::: 1.0491 Yb/s ( 131,133,133,131,333,313,331,311 bytes)

Answer 4

Any idea what's wrong ?
You have created infinte loop which cause it to hang, 1st code has
while( x>1000 ){ x/=1000; s++ }
here each turn decrease x 1000 times so it will finally be equal or lower 1000. 2nd code has
while( x>1000 ){ res = x * 8 / 1000; s++ }
here each turn x is used to compute res but value of x itself never changes, thus you will get either 0 executions of while body or +infinity executions of while body.
Note that But it hangs when I tried to execute it might be observed also in languages other than GNU AWK which do support while construct when you do not change value of variable on which truthiness of condition depends.