[TynesideLUG] bash musings - have I overlooked something?

[Ian Bruntlett]

Hi,

I've created a spreadsheet to gather together what happens when these
things happen:
* Variable (e.g. $BASH_VERSION) interpolation Always occurred except when
single quoted
* Positional parameters (r..g. $1) Always occurred except when single quoted
* backslashed escaped characters (e.g. \t) Always occurred except when NO
quotes

Here are the shell scripts I used to come to those conclusions...

#!/bin/bash
echo hellos - Demonstrating where backslashed escaped characters are done.
echo -e "No quotes     " Hello\tWorld
echo -e "Single quotes " 'Hello\tWorld'
echo -e "Double quotes " 'Hello\tWorld'

#!/bin/bash
echo pos_params - show positional parameter interpolation
echo Param  1 unquoted : $1
echo Param  1 double quoted : "$1"
echo Param  1 single quoted : '$1'
echo Param 10 : ${10}

#!/bin/bash
echo env_vars - show environment variable interpolation
echo "PATH unquoted :      " $PATH
echo "PATH double quoted : " "$PATH"
echo "PATH single quoted : " '$PATH'

Have I missed anything out?

TIA,


Ian

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