shell:warp:98a8e

The command [[ -s ${file} ]] is a conditional expression in the Bash scripting language. It is used to evaluate whether a file exists and has a non-zero size.

Here's a breakdown of the command:

• [[ ... ]] is a conditional expression construct in Bash that allows for more advanced tests compared to the traditional [ ... ] (single brackets) construct.

• -s is an operator within the conditional expression that checks if a file exists and has a size greater than zero. It returns true if the file is non-empty, and false otherwise.

• ${file} is a variable that represents the name or path of the file being tested. The actual value of the file variable will be substituted in its place during execution.

In summary, the [[ -s ${file} ]] command is used to check if the file specified by the value stored in the file variable exists and has a non-zero size. If the condition evaluates to true, further actions can be taken; otherwise, the script can proceed with an alternative course of action.