Bash Bad Substitution Variable

Bash bad substitution when converting string variables to uppercase or lowercase converting strings in your bash script from lowercase to uppercase or viceversa is a common requirement.

Bash bad substitution variable.

This guide shows you how to use parameter expansion modifiers to transform bash shell variables for your scripting needs. I keep getting this message bad substitution. You can use it for manipulating and expanding variables on demands without using external commands such as perl python sed or awk. Here s a simple script that supposedly works.

I ve been working on a bash script using an array. The shell is a rather good tool for manipulating strings. An essential feature of programming is the ability to use a name or a label to refer to some other quantity. Such as a value or a command.

So i googled the problem and every example i came up with supposedly works but not on my computer. The bash shell in particular which is the default on almost every linux distribution and available on almost every unix too has some strong string manipulation utilities built in. Here i m using bash 4 4 19 provide a built in way for uppercasing and lowercasing strings. Bash variables and command substitution using variables to refer to data including the results of a command.

Recent versions of bash e g. Bin bash o 12345 a o b a echo a echo b but when i run it i get this. Substituting strings within variables. Bin bash param sub sh whether a variable has been declared affects triggering of the default option even if the variable is null.