Remove redundant command (#1340)

Remove redundant command

Author: ben

book/01-introduction/sections/installing.asc

@@ -112,7 +112,6 @@ If you're using a RPM-based distribution (Fedora/RHEL/RHEL-derivatives), you als
 [source,console]
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 $ sudo dnf install getopt
-$ sudo apt-get install getopt
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 Additionally, if you're using Fedora/RHEL/RHEL-derivatives, you need to do this