calc - A simple Perl-based calculator for network engineers/researchers
calc [-d] [-p #]This manual page documents calc. This program is an interactive text-based calculator written in Perl supporting GNU readline library. calc is specifically designed for network engineers/researchers since it can easily handle network-related units such as bit, byte, packet, bps, and bit/s.
After invocation, calc displays a prompt "?", and ask for a user to enter an arbitrary expression to be calculated, which must be a valid Perl expression. calc then evaluates the expression as-is, and displays the return value in a decimal format, followed by values in hex, octal, and binary formats.
For typical daily use, the following builtin functions of Perl would be convenient. See perlfunc(1) for information on other builtin functions.
Numeric functions
"abs", "atan2", "cos", "exp", "hex", "int", "log",
"oct", "rand", "sin", "sqrt", "srand"Note that calc supports GNU readline library, so that a user can interactively edit his/her input with Emacs-like (user-configurable) key bindings. See the manual page of GNU readline library for the details.
calc understands the following units, which must be enclosed in square brackets.
s second
m meter
bit bit
bps bit per second
byte, B byte
pkt, packet packetBy default, packet size is assumed to be 1,500 [byte] (i.e., the maximum Ethernet payload size), but it can be changed by -p option.
calc supports the following prefixes.
p pico 10**-12
n nano 10**-9
u micro 10**-6
m milli 10**-3
k, K kilo 10**3
M mega 10**6
G giga 10**9
T tera 10**12
P peta 10**15In calc, the base unit is either second or byte, and all values in other than second or byte are automatically converted. For example, 1,000 [bit/ms] is automatically converted to 125,000 [byte/s]. See "EXAMPLES" for detailed usage of calc.
This section shows an example session with calc.
A simple arithmetic calculation:
? 1+2*(3+4/5)**6
%1 = 6022.872768
1786 hex 13606 oct 00000000 00000000 00010111 10000110
48.18 bit/ms 4.818e+04 bit/s 48.18 Kbit/s 0.04818 Mbit/s
6.023 B/ms 6023 B/s 6.023 KB/s 0.006023 MB/s
0.004015 pkt/ms 4.015 pkt/s 1.807e+12 m 1.807e+09 km Blank spaces are arbitrary.
? 1 + 2 * (3 + 4 / 5) ** 6
%2 = 6022.872768
1786 hex 13606 oct 00000000 00000000 00010111 10000110
48.18 bit/ms 4.818e+04 bit/s 48.18 Kbit/s 0.04818 Mbit/s
6.023 B/ms 6023 B/s 6.023 KB/s 0.006023 MB/s
0.004015 pkt/ms 4.015 pkt/s 1.807e+12 m 1.807e+09 km The previous result can be referred by "%".
? % + 1
%3 = 6023.872768
1787 hex 13607 oct 00000000 00000000 00010111 10000111
48.19 bit/ms 4.819e+04 bit/s 48.19 Kbit/s 0.04819 Mbit/s
6.024 B/ms 6024 B/s 6.024 KB/s 0.006024 MB/s
0.004016 pkt/ms 4.016 pkt/s 1.807e+12 m 1.807e+09 km Past results can be referred by "%N".
? %1 - %2
%4 = 0
0 hex 0 oct 00000000 00000000 00000000 00000000
0 bit/ms 0 bit/s 0 Kbit/s 0 Mbit/s
0 B/ms 0 B/s 0 KB/s 0 MB/s
0 pkt/ms 0 pkt/s 0 m 0 km Perl builtin functions can be used.
? int(%1)
%5 = 6022
1786 hex 13606 oct 00000000 00000000 00010111 10000110
48.18 bit/ms 4.818e+04 bit/s 48.18 Kbit/s 0.04818 Mbit/s
6.022 B/ms 6022 B/s 6.022 KB/s 0.006022 MB/s
0.004015 pkt/ms 4.015 pkt/s 1.807e+12 m 1.807e+09 km
? log(sin(1) + cos(2))
%6 = -0.854903698976914
0 hex 0 oct 00000000 00000000 00000000 00000000
-0.006839 bit/ms -6.839 bit/s -0.006839 Kbit/s -6.839e-06 Mbit/s
-0.0008549 B/ms -0.8549 B/s -0.0008549 KB/s -8.549e-07 MB/s
-5.699e-07 pkt/ms -0.0005699 pkt/s -2.565e+08 m -2.565e+05 km Variables can store values.
? $a = 12345
%7 = 12345
3039 hex 30071 oct 00000000 00000000 00110000 00111001
98.76 bit/ms 9.876e+04 bit/s 98.76 Kbit/s 0.09876 Mbit/s
12.35 B/ms 1.234e+04 B/s 12.35 KB/s 0.01235 MB/s
0.00823 pkt/ms 8.23 pkt/s 3.704e+12 m 3.704e+09 km
? $a + 1
%8 = 12346
303a hex 30072 oct 00000000 00000000 00110000 00111010
98.77 bit/ms 9.877e+04 bit/s 98.77 Kbit/s 0.09877 Mbit/s
12.35 B/ms 1.235e+04 B/s 12.35 KB/s 0.01235 MB/s
0.008231 pkt/ms 8.231 pkt/s 3.704e+12 m 3.704e+09 km
? $b = 12345
%9 = 12345
3039 hex 30071 oct 00000000 00000000 00110000 00111001
98.76 bit/ms 9.876e+04 bit/s 98.76 Kbit/s 0.09876 Mbit/s
12.35 B/ms 1.234e+04 B/s 12.35 KB/s 0.01235 MB/s
0.00823 pkt/ms 8.23 pkt/s 3.704e+12 m 3.704e+09 km
? $a - $b
%10 = 0
0 hex 0 oct 00000000 00000000 00000000 00000000
0 bit/ms 0 bit/s 0 Kbit/s 0 Mbit/s
0 B/ms 0 B/s 0 KB/s 0 MB/s
0 pkt/ms 0 pkt/s 0 m 0 km Example usage of some builtin functions:
? hex("ffff")
%11 = 65535
ffff hex 177777 oct 00000000 00000000 11111111 11111111
524.3 bit/ms 5.243e+05 bit/s 524.3 Kbit/s 0.5243 Mbit/s
65.53 B/ms 6.554e+04 B/s 65.53 KB/s 0.06553 MB/s
0.04369 pkt/ms 43.69 pkt/s 1.966e+13 m 1.966e+10 km
? oct("7777")
%12 = 4095
fff hex 7777 oct 00000000 00000000 00001111 11111111
32.76 bit/ms 3.276e+04 bit/s 32.76 Kbit/s 0.03276 Mbit/s
4.095 B/ms 4095 B/s 4.095 KB/s 0.004095 MB/s
0.00273 pkt/ms 2.73 pkt/s 1.228e+12 m 1.228e+09 km
? sqrt(2943)
%13 = 54.2494239600754
36 hex 66 oct 00000000 00000000 00000000 00110110
0.434 bit/ms 434 bit/s 0.434 Kbit/s 0.000434 Mbit/s
0.05425 B/ms 54.25 B/s 0.05425 KB/s 5.425e-05 MB/s
3.617e-05 pkt/ms 0.03617 pkt/s 1.627e+10 m 1.627e+07 km
? abs(%)
%14 = 54.2494239600754
36 hex 66 oct 00000000 00000000 00000000 00110110
0.434 bit/ms 434 bit/s 0.434 Kbit/s 0.000434 Mbit/s
0.05425 B/ms 54.25 B/s 0.05425 KB/s 5.425e-05 MB/s
3.617e-05 pkt/ms 0.03617 pkt/s 1.627e+10 m 1.627e+07 km
? abs(-%)
%15 = 54.2494239600754
36 hex 66 oct 00000000 00000000 00000000 00110110
0.434 bit/ms 434 bit/s 0.434 Kbit/s 0.000434 Mbit/s
0.05425 B/ms 54.25 B/s 0.05425 KB/s 5.425e-05 MB/s
3.617e-05 pkt/ms 0.03617 pkt/s 1.627e+10 m 1.627e+07 km Convert a transmission rate in several units:
? 123 [packet/ms]
%16 = 184500000
aff3f20 hex 1277637440 oct 00001010 11111111 00111111 00100000
1.476e+06 bit/ms 1.476e+09 bit/s 1.476e+06 Kbit/s 1476 Mbit/s
1.845e+05 B/ms 1.845e+08 B/s 1.845e+05 KB/s 184.5 MB/s
123 pkt/ms 1.23e+05 pkt/s 5.535e+16 m 5.535e+13 km From the above result, one can see that 123 [packet/ms] is equivalent to 1,476 [Mbit/s] with 1,500 [byte] packet.
Product of transmission rate and duration gives the total amount of data transferred.
? % * 10[s]
%17 = 1845000000
6df87740 hex 15576073500 oct 01101101 11111000 01110111 01000000
1.476e+07 bit/ms 1.476e+10 bit/s 1.476e+07 Kbit/s 1.476e+04 Mbit/s
1.845e+06 B/ms 1.845e+09 B/s 1.845e+06 KB/s 1845 MB/s
1230 pkt/ms 1.23e+06 pkt/s 5.535e+17 m 5.535e+14 km Thus, if you continuosly send for 10 [s] at the transmission rate of 123 [packet/ms], the total volume transferred is 1,845 [MB].
Data size divided by duration gives transmission rate.
? 6.4[Gbyte]/120[s]
%18 = 53333333.3333333
32dcd55 hex 313346525 oct 00000011 00101101 11001101 01010101
4.267e+05 bit/ms 4.267e+08 bit/s 4.267e+05 Kbit/s 426.7 Mbit/s
5.333e+04 B/ms 5.333e+07 B/s 5.333e+04 KB/s 53.33 MB/s
35.56 pkt/ms 3.556e+04 pkt/s 1.6e+16 m 1.6e+13 km So, if 6.4 [Gbyte] is trensferred in 120 [s], the transmission rate of the network is 426.7 [Mbit/s].
Calculating the bandwidth-delay product
? 64[packet] * 120[ms]
%19 = 11520
2d00 hex 26400 oct 00000000 00000000 00101101 00000000
92.16 bit/ms 9.216e+04 bit/s 92.16 Kbit/s 0.09216 Mbit/s
11.52 B/ms 1.152e+04 B/s 11.52 KB/s 0.01152 MB/s
0.00768 pkt/ms 7.68 pkt/s 3.456e+12 m 3.456e+09 km which indicates that, for instance, the TCP socket buffer of 11.52 [KB] is at least required for TCP window flow control with its window size of 64 [packet] and the round-trip time of 120 [ms].
Values in meters are converted to seconds --- time to need to travel in the speed of the light.
? 128[km]
%20 = 0.000426666666666666
0 hex 0 oct 00000000 00000000 00000000 00000000
3.413e-06 bit/ms 0.003413 bit/s 3.413e-06 Kbit/s 3.413e-09 Mbit/s
4.267e-07 B/ms 0.0004267 B/s 4.267e-07 KB/s 4.267e-10 MB/s
2.844e-10 pkt/ms 2.844e-07 pkt/s 1.28e+05 m 128 km which shows the light travels 128 [km] in 0.000426 [s].
Conversely, values in seconds are displayed in meters.
? 0.0012[ms]
%21 = 1.2e-06
0 hex 0 oct 00000000 00000000 00000000 00000000
9.6e-09 bit/ms 9.6e-06 bit/s 9.6e-09 Kbit/s 9.6e-12 Mbit/s
1.2e-09 B/ms 1.2e-06 B/s 1.2e-09 KB/s 1.2e-12 MB/s
8e-13 pkt/ms 8e-10 pkt/s 360 m 0.36 km So, one can see that the light travels 0.36 [km] in 0.0012 [ms].
The latest version of calc can is available at
http://www.lsnl.jp/~ohsaki/software/calc/calc
perl(1), perlfunc(1), readline(3)
Hiroyuki Ohsaki <ohsaki[atmark]lsnl.jp>