From 8cd7c230aaa708dffb544887baa85de8f3377251 Mon Sep 17 00:00:00 2001 From: Jonathan Wang Date: Sun, 26 Jun 2016 09:04:11 -0400 Subject: [PATCH] [bash/en] basic parameter expansion, and brace expansion (#1533) * Added brace expansion as well as basic parameter expansion * frogot my name * Update bash.html.markdown Added to parameter expansion --- bash.html.markdown | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/bash.html.markdown b/bash.html.markdown index c2c3e3f1..a62bd167 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -11,6 +11,7 @@ contributors: - ["Rahil Momin", "https://github.com/iamrahil"] - ["Gregrory Kielian", "https://github.com/gskielian"] - ["Etan Reisner", "https://github.com/deryni"] + - ["Jonathan Wang", "https://github.com/Jonathansw" ] filename: LearnBash.sh --- @@ -54,6 +55,13 @@ echo '$Variable' # its name without $. If you want to use the variable's value, you should use $. # Note that ' (single quote) won't expand the variables! +# Parameter expansion ${ }: +echo ${Variable} +# This is a simple usage of parameter expansion +# Parameter Expansion gets a value from a variable. It "expands" or prints the value +# During the expansion time the value or parameter are able to be modified +# Below are other modifications that add onto this expansion + # String substitution in variables echo ${Variable/Some/A} # This will substitute the first occurrence of "Some" with "A" @@ -68,6 +76,12 @@ echo ${Foo:-"DefaultValueIfFooIsMissingOrEmpty"} # This works for null (Foo=) and empty string (Foo=""); zero (Foo=0) returns 0. # Note that it only returns default value and doesn't change variable value. +# Brace Expansion { } +# Used to generate arbitrary strings +echo {1..10} +echo {a..z} +# This will output the range from the start value to the end value + # Builtin variables: # There are some useful builtin variables, like echo "Last program's return value: $?"