Update cheatsheets

bc

@@ -0,0 +1,34 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# bc
+
+> An arbitrary precision calculator language.
+> See also: `dc`.
+> More information: <https://manned.org/man/bc.1>.
+
+- Start an interactive session:
+
+`bc`
+
+- Start an interactive session with the standard math library enabled:
+
+`bc --mathlib`
+
+- Calculate an expression:
+
+`echo '{{5 / 3}}' | bc`
+
+- Execute a script:
+
+`bc {{path/to/script.bc}}`
+
+- Calculate an expression with the specified scale:
+
+`echo 'scale = {{10}}; {{5 / 3}}' | bc`
+
+- Calculate a sine/cosine/arctangent/natural logarithm/exponential function using `mathlib`:
+
+`echo '{{s|c|a|l|e}}({{1}})' | bc --mathlib`