Let’s break down what this script does in detail. The script is named up.sh, authored by GJS (homelab-alpha), and its purpose is to create a function called up that allows users to navigate up a specified number of directory levels in the file system. This is useful for quickly moving up multiple directory levels without having to type cd ../../.. repeatedly.

Here’s a detailed explanation:

Script Metadata

  • Filename: up.sh
  • Author: GJS (homelab-alpha)
  • Date: May 26, 2024
  • Version: 1.0.1
  • Description: The script defines a function up to navigate up a specified number of directory levels in the file system. To use it, you execute the script in a terminal and provide the number of levels to move up.
  • RAW Script: up.sh

Function Definition 

function up() {
  local levels=${1:-1} # Set the default level to 1 if not specified
  local target=""

This defines a function named up. local levels=${1:-1} sets a local variable levels to the first argument passed to the function, or 1 if no argument is provided. This determines how many directory levels to move up. local target="" initializes an empty string target to build the path.


Loop to Construct Path 

  for ((i = 1; i <= levels; i++)); do
    target="../$target"
  done

This loop runs from 1 to the number specified in levels. Each iteration appends ../ to target, effectively building the relative path to navigate up the desired number of directory levels.


Handling Edge Cases 

  if [ -z "$target" ]; then
    target=".."
  fi

This conditional checks if target is empty and sets it to .. if it is. This ensures there’s always a valid path to navigate.


Change Directory Command 

  cd "$target" || return 1 # Go to the target directory or return an error code if it fails
}

The cd "$target" command attempts to change the directory to the constructed target. || return 1 ensures that if the cd command fails (e.g., if the target directory doesn’t exist), the function will return an error code 1.


Usage Examples

Move up one directory level 

up

This is equivalent to cd ...


Move up three directory levels 

up 3

This would navigate up three levels in the directory hierarchy, equivalent to cd ../../../.


Conclusion

This script is simple but powerful, allowing users to navigate their filesystem more efficiently by specifying the number of levels to move up directly within the command.

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Last updated 01 Sep 2024, 10:22 CEST . history