[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
This commit is contained in:
Jonathan Wang 2016-06-26 09:04:11 -04:00 committed by ven
parent d9caa2436e
commit 8cd7c230aa

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@ -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: $?"