diff options
Diffstat (limited to 'bash.html.markdown')
| -rw-r--r-- | bash.html.markdown | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/bash.html.markdown b/bash.html.markdown index 0c097c27..cb805da7 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -25,7 +25,7 @@ Nearly all examples below can be a part of a shell script or executed directly i [Read more here.](http://www.gnu.org/software/bash/manual/bashref.html) ```bash -#!/bin/bash +#!/usr/bin/env bash # First line of the script is shebang which tells the system how to execute # the script: http://en.wikipedia.org/wiki/Shebang_(Unix) # As you already figured, comments start with #. Shebang is also a comment. @@ -74,7 +74,7 @@ echo ${Variable/Some/A} # => A string # Substring from a variable Length=7 -echo ${Variable:0:Length} # => Some st +echo ${Variable:0:$Length} # => Some st # This will return only the first 7 characters of the value # Default value for variable @@ -83,6 +83,25 @@ 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 forth +echo ${array0[@]:3:2} # => "four five" +# Print all elements. Each of them on new line. +for i in "${array0[@]}"; do + echo "$i" +done + # Brace Expansion { } # Used to generate arbitrary strings echo {1..10} # => 1 2 3 4 5 6 7 8 9 10 @@ -155,6 +174,13 @@ then echo "This will run if $Name is Daniya OR Zach." fi +# Redefine command 'ping' as alias to send only 5 packets +alias ping='ping -c 5' +# Escape alias and use command with this name instead +\ping 192.168.1.1 +# Print all aliases +alias -p + # Expressions are denoted with the following format: echo $(( 10 + 5 )) # => 15 |