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@ -54,8 +54,7 @@ You can sort, filter, and aggregate the data,
use a SQL style join statement between two tables,
and use functional programming patterns to manipulate tables.
Some examples of things that nushell enables with this structured data passing
through pipelines includes:
Some examples of things that nushell enables with this structured data passing through pipelines includes:
{{<highlight sh>}}
# show all files recursively that were modified in the last week
@ -123,26 +122,23 @@ update bytes_sent {into int}
{{</highlight>}}
(each line has a comment explaining what it does, for those unfamiliar with the nushell language)
Now that we have it in nushell tables, we can bring all of nushells tools to
bear on the data. For example, we could plot a histogram of the most common
ips, just by piping the whole thing into `histogram ip`. We could easily
calculate the average bytes sent per request. We could group the records by the
day or hour they happened, and analyze each of those groups independently. And
we can do all of that after arbitrarily filtering, sorting, or otherwise
transforming the table.
Now that we have it in nushell tables, we can bring all of nushells tools to bear on the data.
For example, we could plot a histogram of the most common ips, just by piping the whole thing into `histogram ip`.
We could easily calculate the average bytes sent per request.
We could group the records by the day or hour they happened, and analyze each of those groups independently.
And we can do all of that after arbitrarily filtering, sorting, or otherwise transforming the table.
While it would be a pretty long one liner if we decided to put it in a single
line, its still quite easy and straightforward to write.
While it would be a pretty long one liner if we decided to put it in a single line,
its still quite easy and straightforward to write.
Most log formats and command outputs are similarly straightforward.
## Defining custom commands, with built-in arg parsing
Nushell has a feature called Custom Commands, which fill the same purpose as
functions in other shells/programming languages, but are a bit more featurefull
than traditional POSIX shell functions.
Nushell has a feature called Custom Commands,
which fill the same purpose as functions in other shells/programming languages,
but are a bit more featurefull than traditional POSIX shell functions.
First of all, nushell custom commands specify the number of positional arguments
they take.
First of all, nushell custom commands specify the number of positional arguments they take.
{{<highlight sh>}}
def recently-modified [cutoff] {
@ -168,8 +164,8 @@ def recently-modified [cutoff: string] {
}
{{</highlight>}}
You can give the arguments a default value, making it optional, (can be combined
with a type specification)
You can give the arguments a default value, making it optional.
(can be combined with a type specification)
{{<highlight sh>}}
def recently-modified [cutoff = '1 week ago'] {
@ -181,9 +177,8 @@ def recently-modified [cutoff = '1 week ago'] {
}
{{</highlight>}}
You have flag parsing, complete with short flags, is included as well. (A
flag without a type will be taken as a boolean flag, set by its presence or
absence)
You have flag parsing, complete with short flags, is included as well.
(A flag without a type will be taken as a boolean flag, set by its presence or absence)
{{<highlight sh>}}
def recently-modified [cutoff: string = '1 week ago' --older-than (-o)] {
@ -203,8 +198,8 @@ def recently-modified [cutoff: string = '1 week ago' --older-than (-o)] {
}
{{</highlight>}}
And finally, you can add a rest command at the end, allowing you to take a variable number of
arguments.
And finally, you can add a rest command at the end, allowing you to take a variable number of arguments.
{{<highlight sh>}}
def recently-modified [--cutoff = '1 week ago' ...paths] {
for $path in $paths {
@ -217,8 +212,8 @@ def recently-modified [--cutoff = '1 week ago' ...paths] {
}
{{</highlight>}}
All of the specified parameters are automatically added to a generated `--help`
page, along with a documentation comments, so that the following code block:
All of the specified parameters are automatically added to a generated `--help` page,
along with a documentation comments, so that the following code block:
{{<highlight sh>}}
# display recently modified files
@ -260,13 +255,11 @@ Input/output types:
╰───┴───────┴────────╯
```
(the input/output table at the bottom has to do with how the command is used in
a pipeline, and is covered in more detail in the
[book](https://www.nushell.sh/book/command_signature.html))
(the input/output table at the bottom has to do with how the command is used in a pipeline,
and is covered in more detail in the [book](https://www.nushell.sh/book/command_signature.html))
This addition of easy argument parsing makes it incredibly convenient to add
command line arguments to your scripts and functions, something that is anything
but easy in POSIX shells.
This addition of easy argument parsing makes it incredibly convenient to add command line arguments to your scripts and functions,
something that is anything but easy in POSIX shells.
## Error messages
@ -296,8 +289,8 @@ done
(standard_in) 1: syntax error
{{</highlight>}}
This error tells you nothing about what went wrong, and your only option is to
start print debugging.
This error tells you nothing about what went wrong,
and your only option is to start print debugging.
The equivalent in nushell would be:
@ -305,8 +298,9 @@ The equivalent in nushell would be:
> ls | get size | each {|item| $item / 1000}
{{</highlight>}}
If we typo the size column, we get a nice error telling us exactly what we got
wrong, and where in the pipeline the error and value originated. Much better.
If we typo the size column, we get a nice error telling us exactly what we got wrong,
and where in the pipeline the error and value originated.
Much better.
{{<highlight sh "linenos=false">}}
> ls | get szie | each {|item| $item / 1000}
@ -325,8 +319,8 @@ Error: nu::shell::column_not_found
Now, nushell is not finished yet.
As I write, I am running version 0.91 of nu.
Similar to fish, it not being a POSIX shell means that you still need to drop
into bash or zsh in order to source env files in order to,
Similar to fish,
it not being a POSIX shell means that you still need to drop into bash or zsh in order to source env files in order to,
for example, use a cross-compiling c/c++ sdk.
(thankfully, python virtualenvs already come with a nu script for you to source,
so doing python dev will not require you to launch a POSIX shell)
@ -362,14 +356,12 @@ def recently-modified [
> recently-modified --cutoff '2 weeks ago' ./
{{</highlight>}}
Its certainly not the most ergonomic, but seems to be the best way at the moment
to make 'scripts' that are integrated with the rest of nushell.
Its certainly not the most ergonomic,
but seems to be the best way at the moment to make 'scripts' that are integrated with the rest of nushell.
## So, overall, is it worth it?
Nushell is certainly an promising project, and I will almost certainly be
continuing to use it as my daily shell. It cant do everything, but dropping into
zsh for a task or two every once in a while isnt that big a deal for me, and
having access to such a powerful shell by default has made other tasks much
easier for me. If you regularly use pipelines in your default shell, consider
giving Nushell a try.
Nushell is certainly an promising project, and I will almost certainly be continuing to use it as my daily shell.
It cant do everything, but dropping into zsh for a task or two every once in a while isnt that big a deal for me,
and having access to such a powerful shell by default has made other tasks much easier.
If you regularly use pipelines in your default shell, consider giving Nushell a try.