Update cheatsheets

tldr/linux/mopac

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+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# mopac
+
+> MOPAC (Molecular Orbital PACkage) is a semiempirical quantum chemistry program based on Dewar and Thiel's NDDO approximation.
+> More information: <https://github.com/openmopac/mopac>.
+
+- Perform calculations according to an input file (`.mop`, `.dat`, and `.arc`):
+
+`mopac {{path/to/input_file}}`
+
+- Minimal working example with HF that writes to the current directory and streams the output file:
+
+`touch test.out; echo "PM7
+#comment
+
+H 0.95506 0.05781 -0.03133
+F 1.89426 0.05781 -0.03133" > test.mop; mopac test.mop & tail -f test.out`