Modern advanced shells have a method to reference the value of a variable whose name is stored in another variable. Unfortunately the method ... ... <看更多>

In bash, you can use ${!variable} to use variable variables. foo="something" bar="foo" echo "${!bar}" # something. ... <看更多>

1 Variables. Assign a value to a variable using a single equals sign and no spaces, then use the echo function to display the value of the variable. ... <看更多>

When a variable is exported to become an environment variable it becomes available to the shell, to sub shells and every command in the ... ... <看更多>

Checking if a variable is null in Bash (unbound variable check) - var_defined.sh. ... echo "CHECK 1: variable 'VAR' is set, its content is '$VAR'";. ... <看更多>