defines a handy function for quick calculations from cli.
once defined:
? 10*2+3
Show Sample Output
Easily convert numbers to their representations in different bases. Passing "ibase=16; obase=8; F2A" to bc will convert F2A (3882 in decimal) from Hex to Octal, and so on. Show Sample Output
A bitcoin "brainwallet" is a secret passphrase you carry in your brain. The Bitcoin Brainwallet Private Key Base58 Encoder is the third of three functions needed to calculate a bitcoin PRIVATE key from your "brainwallet" passphrase. This base58 encoder uses the obase parameter of the amazing bc utility to convert from ASCII-hex to base58. Tech note: bc inserts line continuation backslashes, but the "read s" command automatically strips them out. I hope that one day base58 will, like base64, be added to the amazing openssl utility. Show Sample Output
The "proportional set size" is probably the closest representation of how much active memory a process is using in the Linux virtual memory stack. This number should also closely represent the %mem found in ps(1), htop(1), and other utilities. Show Sample Output
To do hex to binary: echo 'ibase=16; obase=2; 16*16' | bc # prints: 111100100 To do 16*16 from decimal to hex: echo 'ibase=10; obase=16; 16*16' | bc # prints: 100 You get the idea... Alternatively, run bc in interactive mode (see man page) Show Sample Output
Use the standard calculator bc to convert decimals to hex Show Sample Output
allows you to use floating point operations in shell scripts Show Sample Output
-l auto-selects many more digits (but you can round/truncate in your head, right) plus it loads a few math functions like sin(). Show Sample Output
POSIX compliant arithmetic evaluation. = 10*2+3 Show Sample Output
Useful for quick calculations at the command line. $math_expr is any arithmetic expression (see sample output): 4.5*16+3^2 s(3.1415926/2) More options in the bc man page. Show Sample Output
When you've got a list of numbers each on its row, the ECHO command puts them on a simple line, separated by space. You can then substitute the spaces with an operator. Finally, pipe it to the BC program. Show Sample Output
using bc is for sissies. dc is much better :-D Polish notation will rule the world... Show Sample Output
Exactly the same number of characters, exactly the same results, but with bc Show Sample Output
Print out your age in days in binary. Today's my binary birthday, I'm 2^14 days old :-) . This command does bash arithmatic $(( )) on two dates: Today: $(date +%s) Date of birth: $(date +%s -d YYYY-MM-DD) The dates are expressed as the number of seconds since the Unix epoch (Jan 1970), so we devide the difference by 86400 (seconds per day). . Finally we pipe "obase=2; DAYS-OLD" into bc to convert to binary. (obase == output base) Show Sample Output
# 4 cores with 2500 pi digits
CPUBENCH 4 2500
.
every core will use 100% cpu and you can see how fast they calculate it.
if you do 50000 digitits and more it can take hours or days
Show Sample Output
If you want a sequence that can be plotted, do: seq 8 | awk '{print "e(" $0 ")" }' | bc -l | awk '{print NR " " $0}' Other bc functions include s (sine), c (cosine), l (log) and j (bessel). See the man page for details. Show Sample Output
Calculate pi from the infinite series 4/1 - 4/3 + 4/5 - 4/7 + ... This expansion was formulated by Gottfried Leibniz: http://en.wikipedia.org/wiki/Leibniz_formula_for_pi I helped rubenmoran create the sum of a sequence of numbers and he replied with a command for the sequence: 1 + 2 -3 + 4 ... This set me thinking. Transcendental numbers! seq provides the odd numbers 1, 3, 5 sed turns them into 4/1 4/3 4/5 paste inserts - and + bc -l does the calculation Note: 100 million iterations takes quite a while. 1 billion and I run out of memory. Show Sample Output
Same functionality without using bash functions. Show Sample Output
Inspired by Tatsh's comment.
Adds up the used disk space on all hard drives that are directly connected to the machine (i.e. no network mounts etc.) Assumes there are no IDE drives present. Show Sample Output
This shell calculator uses POSIX features only and is therefore portable. By default the number of significant figures is limited to 8 with trailing zeros stripped, resembling the display of a basic pocket calculator. You might want to increase this to 12 to emulate a scientific calculator. Show Sample Output
You could have that little benchmark run on all cores in parallel, as a multi-core benchmark or stress test First find the number of cores, then have parallel iterate over that in, well, parallel Show Sample Output
Broken in two parts, first get the number of cores with cat /proc/cpuinfo |grep proc|wc -l and create a integer sequence with that number (xargs seq), then have GNU parallel loop that many times over the given command. Cheers! Show Sample Output
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