finished nushell post

content/posts/nushell.md

@@ -1,7 +1,6 @@
 +++
 title = "Nushell first impressions"
 date = 2024-03-01T11:34:04-06:00
-draft = true
 +++
 
 Ive been trying out a bunch of new shell utilities lately,
@@ -59,7 +58,7 @@ Some examples of things that nushell enables with this structured data passing
 through pipelines includes:
 
 {{<highlight sh>}}
-# show all files recurisively that were modified in the last week
+# show all files recursively that were modified in the last week
 ls **/* | where modified > (
     # create timestamp from relative human readable string.
     '1 week ago' | into datetime
@@ -147,7 +146,7 @@ they take.
 
 {{<highlight sh>}}
 def recently-modified [cutoff] {
-# show all files recurisively that were modified after a specified cutoff
+# show all files recursively that were modified after a specified cutoff
     # show all files recurisively that were modified after a specified cutoff
     ls **/* | where modified > (
         # create timestamp from input
@@ -160,7 +159,7 @@ You can optionally give the arguments a type
 
 {{<highlight sh>}}
 def recently-modified [cutoff: string] {
-# show all files recurisively that were modified after a specified cutoff
+# show all files recursively that were modified after a specified cutoff
     # show all files recurisively that were modified after a specified cutoff
     ls **/* | where modified > (
         # create timestamp from input
@@ -174,7 +173,7 @@ with a type specification)
 
 {{<highlight sh>}}
 def recently-modified [cutoff = '1 week ago'] {
-    # show all files recurisively that were modified after a specified cutoff
+    # show all files recursively that were modified after a specified cutoff
     ls **/* | where modified > (
         # create timestamp from input
         $cutoff | into datetime
@@ -189,13 +188,13 @@ absence)
 {{<highlight sh>}}
 def recently-modified [cutoff: string = '1 week ago' --older-than (-o)] {
     if $older_than {
-        # show all files recurisively that were modified after a specified cutoff
+        # show all files recursively that were modified after a specified cutoff
         ls **/* | where modified > (
             # create timestamp from input
             $cutoff | into datetime
         )
     } else {
-        # show all files recurisively that were modified before a specified cutoff
+        # show all files recursively that were modified before a specified cutoff
         ls **/* | where modified < (
             # create timestamp from input
             $cutoff | into datetime
@@ -209,7 +208,7 @@ arguments.
 {{<highlight sh>}}
 def recently-modified [--cutoff = '1 week ago' ...paths] {
     for $path in $paths {
-        # show all files recurisively that were modified after a specified cutoff
+        # show all files recursively that were modified after a specified cutoff
         ls $path | where modified > (
             # create timestamp from input
             $cutoff | into datetime
@@ -228,7 +227,7 @@ def recently-modified [
     ...paths # paths to consider
 ] {
     for $path in $paths {
-        # show all files recurisively that were modified after a specified cutoff
+        # show all files recursively that were modified after a specified cutoff
         ls $path | where modified > (
             # create timestamp from input
             $cutoff | into datetime
@@ -271,8 +270,56 @@ but easy in POSIX shells.
 
 ## Error messages
 
-Nushell brings with it great, self explanatory error messages.
-For example, if we do this:
+Nushell brings with it great error messages that explain where the error
+occurred. In bash, if we have a loop like:
+{{<highlight sh "linenos=false">}}
+$ for i in $(ls -l | tr -s " " | cut --fields=5 --delimiter=" "); do
+echo "$i / 1000" | bc
+done
+{{</highlight>}}
+
+This gets the sizes of all the files in kib. But what if we typo something?
+
+{{<highlight sh "linenos=false">}}
+$ for i in $(ls -l | tr -s " " | cut --fields=6 --delimiter=" "); do
+echo "$i / 1000" | bc
+done
+
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+(standard_in) 1: syntax error
+{{</highlight>}}
+
+This error tells you nothing about what went wrong, and your only option is to
+start print debugging.
+
+The equivalent in nushell would be:
+
+{{<highlight sh "linenos=false">}}
+> 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.
+
+{{<highlight sh "linenos=false">}}
+> ls | get szie | each {|item| $item / 1000}
+Error: nu::shell::column_not_found
+
+  × Cannot find column
+   ╭─[entry #1:1:1]
+ 1 │ ls | get szie | each {|item| $item / 1000}
+   · ─┬       ──┬─
+   ·  │         ╰── cannot find column 'szie'
+   ·  ╰── value originates here
+   ╰────
+{{</highlight>}}
 
 ## Whats not there yet
 
@@ -289,4 +336,39 @@ invoking them from within nu treats them as external commands,
 meaning they take in and pass out plain text,
 rather than the structured data that you would get with a proper custom command
 or nu builtin.
-//explain the best workaround.
+The best workaround Ive found so far is instead of making scripts that you run
+directly, you define a custom command in the script file, `use` that file, and
+then run the custom command, like this:
+
+{{<highlight sh>}}
+# recently-modified.nu
+# display recently modified files
+def recently-modified [
+    --cutoff = '1 week ago' # cutoff to be considered 'recently modified'
+    ...paths # paths to consider
+] {
+    for $path in $paths {
+        # show all files recursively that were modified after a specified cutoff
+        ls $path | where modified > (
+            # create timestamp from input
+            $cutoff | into datetime
+        )
+    }
+}
+{{</highlight>}}
+
+{{<highlight sh "linenos=false">}}
+> use recently-modified.sh
+> recently-modifiued --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.
+
+## So, overall, is it worth it?
+
+Nushell is certainly an interesting 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.