[Short Tip] Get all columns in a table

When working with larger data structures in Nushell, there are often tables that are wider than the terminal has width, resulting in some columns truncated, indicated by the three dots .... But how can we expand the dots?

❯ ls -la
╭───┬──────────────────┬──────┬────────┬──────────┬─────╮
│ # │       name       │ type │ target │ readonly │ ... │
├───┼──────────────────┼──────┼────────┼──────────┼─────┤
│ 0 │ 213-3123-43432.p │ file │        │ false    │ ... │
│   │ df               │      │        │          │     │
│ 1 │ barcode-picture. │ file │        │ false    │ ... │
│   │ jpg              │      │        │          │     │
│ 2 │ print-me-by-tomo │ file │        │ false    │ ... │
│   │ rrow.pdf         │      │        │          │     │
╰───┴──────────────────┴──────┴────────┴──────────┴─────╯

The answer is simple, but surprisingly, not easily found. The “Working with tables” documentation of Nushell weirdly doesn’t tell, for example. The trick is to use the command columns to get a list of all column names:

❯ ls -la|columns
╭────┬───────────╮
│  0 │ name      │
│  1 │ type      │
│  2 │ target    │
│  3 │ readonly  │
│  4 │ mode      │
│  5 │ num_links │
│  6 │ inode     │
│  7 │ user      │
│  8 │ group     │
│  9 │ size      │
│ 10 │ created   │
│ 11 │ accessed  │
│ 12 │ modified  │
╰────┴───────────╯

And once you know that command, you can easily find the corresponding Nushell documentation: nushell.sh/commands/docs/columns.html

Short Tip: egrep – using grep with more than one expression

I stumbled across an old blog post of mine about using grep with more than one expression: in the old days I used -e several times, one for each new expression. But as stressed in the comments that way is neither convenient nor reliable on ll platforms. And I have developed as well, so today I usually use egrep if I need to grep for several expressions. Thus, here are some short notes about using it.

The multiple arguments you are searching for a passed to egrep separated by pipes. For example, if you want to grep the output of lspci for all audio and video controllers, the correct command is:

$ lspci|egrep -i 'audio|vga'
00:05.0 Audio device: NVIDIA Corporation MCP61 High Definition Audio (rev a2)
00:0d.0 VGA compatible controller: NVIDIA Corporation C61 [GeForce 6150SE nForce 430] (rev a2)

( Yes, I know, I write my blog post on pretty old hardware right now 😉 )

egrep does understand more than two expressions, so you can use the option like $STRING_1|$STRING_2|$STRING_3|.... But don’t forget to include the high tics ' in the command: these ensure that the pipe is used as a separator instead of being interpreted by your shell.