This recipe walks through some simple text-replacement techniques and parameter-expansion shorthands available in Bash. A few simple techniques can help avoid writing multiple lines of code.
Text slicing and parameter operations
How to do it...
Let's get into the tasks.
Replace some text from a variable:
$ var="This is a line of text"
$ echo ${var/line/REPLACED}
This is a REPLACED of text"
The line word is replaced with REPLACED.
We can produce a substring by specifying the start position and string length, using the following syntax:
${variable_name:start_position:length}
Print from the fifth character onwards:
$ string=abcdefghijklmnopqrstuvwxyz
$ echo ${string:4}
efghijklmnopqrstuvwxyz
Print eight characters starting...