diff options
| -rw-r--r-- | bash.html.markdown | 50 |
1 files changed, 26 insertions, 24 deletions
diff --git a/bash.html.markdown b/bash.html.markdown index 3f1e8b70..53c3d96c 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -102,39 +102,41 @@ 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. -# Declare an array with 6 elements -array0=(one two three four five six) -# Print first element -echo $array0 # => "one" -# Print first element -echo ${array0[0]} # => "one" -# Print all elements -echo ${array0[@]} # => "one two three four five six" -# Print number of elements -echo ${#array0[@]} # => "6" -# Print number of characters in third element -echo ${#array0[2]} # => "5" -# Print 2 elements starting from fourth -echo ${array0[@]:3:2} # => "four five" -# Print all elements. Each of them on new line. -for i in "${array0[@]}"; do - echo "$i" +# Declare an array with 6 elements: +array=(one two three four five six) +# Print the first element: +echo "${array[0]}" # => "one" +# Print all elements: +echo "${array[@]}" # => "one two three four five six" +# Print the number of elements: +echo "${#array[@]}" # => "6" +# Print the number of characters in third element +echo "${#array[2]}" # => "5" +# Print 2 elements starting from fourth: +echo "${array[@]:3:2}" # => "four five" +# Print all elements each of them on new line. +for item in "${array[@]}"; do + echo "$item" done -# Brace Expansion { } -# Used to generate arbitrary strings -echo {1..10} # => 1 2 3 4 5 6 7 8 9 10 -echo {a..z} # => a b c d e f g h i j k l m n o p q r s t u v w x y z -# This will output the range from the start value to the end value - # Built-in variables: -# There are some useful built-in variables, like +# There are some useful built-in variables, like: echo "Last program's return value: $?" echo "Script's PID: $$" echo "Number of arguments passed to script: $#" echo "All arguments passed to script: $@" echo "Script's arguments separated into different variables: $1 $2..." +# Brace Expansion {...} +# used to generate arbitrary strings: +echo {1..10} # => 1 2 3 4 5 6 7 8 9 10 +echo {a..z} # => a b c d e f g h i j k l m n o p q r s t u v w x y z +# This will output the range from the start value to the end value. +# Note that you can't use variables here: +from=1 +to=10 +echo {$from..$to} # => {$from..$to} + # Now that we know how to echo and use variables, # let's learn some of the other basics of bash! |