Converting Data to Text for External Commands and Understanding Nushell Command Output

# => │ 32 │ /usr/share/nvim/runtime/tutor │ dir │ 4.1 KB │ 2 days ago │ # => ├────┼───────────────────────────────────────┼──────┼─────────┼───────────────┤ # => │ # │ name │ type │ size │ modified │ # => ╰────┴───────────────────────────────────────┴──────┴─────────┴───────────────╯ ``` You decided to use `grep` and [pipe](https://www.nushell.sh/book/pipelines.html) the result to external `^ls` ```nu ls /usr/share/nvim/runtime/ | get name | ^grep tutor | ^ls -la $in # => ls: cannot access ''$'\342\224\202'' 32 '$'\342\224\202'' /usr/share/nvim/runtime/tutor '$'\342\224\202\n': No such file or directory ``` What's wrong? Nushell renders lists and tables (by adding a border with characters like `╭`,`─`,`┬`,`╮`) before piping them as text to external commands. If that's not the behavior you want, you must explicitly convert the data to a string before piping it to an external. For example, you can do so with [`to text`](/commands/docs/to_text.md): ```nu ls /usr/share/nvim/runtime/ | get name | to text | ^grep tutor | tr -d '\n' | ^ls -la $in # => total 24 # => drwxr-xr-x@ 5 pengs admin 160 14 Nov 13:12 . # => drwxr-xr-x@ 4 pengs admin 128 14 Nov 13:42 en # => -rw-r--r--@ 1 pengs admin 5514 14 Nov 13:42 tutor.tutor # => -rw-r--r--@ 1 pengs admin 1191 14 Nov 13:42 tutor.tutor.json ``` (Actually, for this simple usage you can just use [`find`](/commands/docs/find.md)) ```nu ls /usr/share/nvim/runtime/ | get name | find tutor | ansi strip | ^ls -al ...$in ``` ## Command Output in Nushell Unlike external commands, Nushell commands are akin to functions. Most Nushell commands do not print anything to `stdout` and instead just return data. ```nu do { ls; ls; ls; "What?!" } ``` This means that the above code will not display the files under the current directory three times. In fact, running this in the shell will only display `"What?!"` because that is the value returned by the `do` command in this example. However, using the system `^ls` command instead of `ls` would indeed print the directory thrice because `^ls` does print its result once it runs. Knowing when data is displayed is important when using configuration variables that affect the display output of commands such as `table`. ```nu do { $env.config.table.mode = "none"; ls } ``` For instance, the above example sets the `$env.config.table.mode` configuration variable to `none`, which causes the `table` command to render data without additional borders. However, as it was shown earlier, the command is effectively equivalent to ```nu do { $env.config.table.mode = "none"; ls } | table ``` Because Nushell `$env` variables are [scoped](https://www.nushell.sh/book/environment.html#scoping), this means that the `table` command in the example is not affected by the environment modification inside the `do` block and the data will not be shown with the applied configuration. When displaying data early is desired, it is possible to explicitly apply `| table` inside the scope, or use the `print` command. ```nu do { $env.config.table.mode = "none"; ls | table } do { $env.config.table.mode = "none"; print (ls) } ```

This section elaborates on the previous example by demonstrating how to correctly pipe the output of `ls` to external commands like `grep` and `ls` using `to text` to avoid formatting issues. It also briefly mentions using `find` as a simpler alternative. Furthermore, it explains the difference between Nushell commands and external commands, emphasizing that Nushell commands typically return data rather than printing to stdout. It also demonstrates how environment variables scoped within `do` blocks might not affect commands outside the block, and suggests using `| table` or `print` to display data with the desired configuration.