docs: Improve README

README.md

@@ -23,10 +23,39 @@ go install -v github.com/Tom5521/fsize@latest
 However, I recommend this method more:
 
 Basically because go takes a long time to automatically detect the newest tags.
+And also this installs the completions
 
 ```bash
 git clone https://github.com/Tom5521/fsize.git
-just go-install # or "sudo just linux-install" which will copy it to /usr/bin
+just linux-install # or "sudo just linux-install" which will copy it to /usr/bin
+```
+
+## Documentation
+
+```
+Displays the file/folder properties.
+
+Usage:
+  fsize [flags]
+
+Flags:
+  -c, --config strings        Configure the variables used for preferences
+                              Example: "fsize --config 'AlwaysShowProgress=true,AlwaysPrintOnWalk=false'".
+
+                              To see the available variables and their values run "fsize --print-settings".
+      --gen-bash-completion   Generate a completion file for bash
+                              if any, the first argument will be taken as output file.
+      --gen-fish-completion   Generate a completion file for fish
+                              if any, the first argument will be taken as output file.
+      --gen-zsh-completion    Generate a completion file for zsh
+                              if any, the first argument will be taken as output file.
+  -h, --help                  help for fsize
+      --no-walk               Skips walking inside the directories.
+      --no-warns              Hide possible warnings.
+      --print-on-walk         Prints the name of the file being walked if a directory has been selected.
+      --print-settings        Prints the current configuration values.
+  -p, --progress              Displays a file count and progress bar when counting and summing file sizes. (default true)
+  -v, --version               version for fsize
 ```
 
 Or by copying one of the