ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux-gnu]

Usage: ruby2.5 [switches] [--] [programfile] [arguments] -0[octal] specify record separator (\0, if no argument) -a autosplit mode with -n or -p (splits $_ into $F) -c check syntax only -Cdirectory cd to directory before executing your script -d, --debug set debugging flags (set $DEBUG to true) -e 'command' one line of script. Several -e's allowed. Omit [programfile] -Eex[:in], --encoding=ex[:in] specify the default external and internal character encodings -Fpattern split() pattern for autosplit (-a) -i[extension] edit ARGV files in place (make backup if extension supplied) -Idirectory specify $LOAD_PATH directory (may be used more than once) -l enable line ending processing -n assume 'while gets(); ... end' loop around your script -p assume loop like -n but print line also like sed -rlibrary require the library before executing your script -s enable some switch parsing for switches after script name -S look for the script using PATH environment variable -T[level=1] turn on tainting checks -v, --verbose print version number, then turn on verbose mode -w turn warnings on for your script -W[level=2] set warning level; 0=silence, 1=medium, 2=verbose -x[directory] strip off text before #!ruby line and perhaps cd to directory --copyright print the copyright --dump={insns|parsetree|...}[,...] dump debug information. see below for available dump list --enable={gems|rubyopt|...}[,...], --disable={gems|rubyopt|...}[,...] enable or disable features. see below for available features --external-encoding=encoding, --internal-encoding=encoding specify the default external or internal character encoding --version print the version --help show this message, -h for short message Dump List: insns instruction sequences yydebug yydebug of yacc parser generator parsetree AST parsetree_with_comment AST with comments Features: gems rubygems (default: enabled) did_you_mean did_you_mean (default: enabled) rubyopt RUBYOPT environment variable (default: enabled) frozen-string-literal freeze all string literals (default: disabled)