How to make variables as read only in bash shell linux ?
Variables in Linux can be made read only using the keyword “readonly”.
For example, if we want a variable to contain a value say 10 and must not be changed then we can achieve this using readonly.
Making a variable read only
### 1. Creating variable and assigning value ngelinux:~ saket$ a=NGELinux ngelinux:~ saket$ echo $a NGELinux ### 2. Making a variable read only ngelinux:~ saket$ a=NGEL ngelinux:~ saket$ echo $a NGEL ngelinux:~ saket$ readonly a ### 3. Read-only variable can't be modified. ngelinux:~ saket$ a=NGELinux_again -bash: a: readonly variable ngelinux:~ saket$ ### 4. We can't unset a read only variable. ngelinux:~ saket$ unset a -bash: unset: a: cannot unset: readonly variable
Still if you want to unset a read-only variable, then check out this article here.