nushell/docs/commands/where.md
2021-06-07 15:21:31 -05:00

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# where
This command filters the content of a table based on a condition passed as a parameter, which must be a boolean expression making use of any of the table columns. Other commands such as `ls` are capable of feeding `where` with their output through pipelines.
Where has two general forms:
- `where <column_name> <comparison> <value>`
- `where <column_name>`
## Where with comparison
In the first form, `where` is passed a column name that the filter will run against. Next, is the operator used to compare this column to its value. The following operators are supported:
- `<` (less than)
- `<=` (less than or equal)
- `>` (greater than)
- `>=` (greater than or equal)
- `!=` (not equal)
- `==` (equal)
Strings have two additional operators:
- `=~` (fuzzy match to allow)
- `!~` (fuzzy match to not allow)
Dates can also be compared using the duration types. For example, `where accessed > 2wk` will check the date in accessed to see if it's greater than 2 weeks ago. Durations currently allow these abbreviations:
- `1sec` (one second)
- `1min` (one minute)
- `1hr` (one hour)
- `1day` (one day)
- `1wk` (one week)
## Boolean check
Where with the form `| where readonly` is used to check boolean values. For example, the command `ls --long | where readonly` will list only those files that are readonly.
## Usage
```shell
> [input-command] | where [condition]
```
## Examples
```shell
> ls | where size > 4kb
───┬────────────┬──────┬──────────┬─────────────
# │ name │ type │ size │ modified
───┼────────────┼──────┼──────────┼─────────────
0 │ Cargo.lock │ File │ 113.3 KB │ 53 mins ago
1 │ Cargo.toml │ File │ 4.6 KB │ 53 mins ago
2 │ README.md │ File │ 15.8 KB │ 2 mins ago
───┴────────────┴──────┴──────────┴─────────────
```
```shell
> ps | where cpu > 0
───┬───────┬──────────────────┬─────────┬────────┬──────────┬─────────
# │ pid │ name │ status │ cpu │ mem │ virtual
───┼───────┼──────────────────┼─────────┼────────┼──────────┼─────────
017917 │ nu_plugin_core_p │ Running │ 4.1678 │ 2.1 MB │ 4.8 GB
114717 │ Discord Helper ( │ Running │ 1.6842 │ 371.9 MB │ 8.0 GB
214713 │ Discord Helper │ Running │ 0.2099 │ 27.8 MB │ 5.8 GB
314710 │ Discord │ Running │ 0.0883 │ 105.4 MB │ 7.0 GB
49643 │ Terminal │ Running │ 4.0313 │ 266.4 MB │ 7.6 GB
57864 │ Microsoft.Python │ Running │ 0.9828 │ 340.9 MB │ 8.0 GB
624402 │ Code Helper (Ren │ Running │ 1.0644 │ 337.3 MB │ 8.4 GB
724401 │ Code Helper (Ren │ Running │ 1.0031 │ 593.5 MB │ 8.6 GB
8519 │ EmojiFunctionRow │ Running │ 0.2063 │ 52.7 MB │ 7.5 GB
9376 │ CommCenter │ Running │ 0.1620 │ 30.0 MB │ 6.5 GB
───┴───────┴──────────────────┴─────────┴────────┴──────────┴─────────
```
```shell
> ls -l | where accessed <= 1wk
───┬────────────────────┬──────┬────────┬──────────┬───────────┬─────────────┬───────┬──────────┬──────────────┬─────────────┬─────────────
# │ name │ type │ target │ readonly │ mode │ uid │ group │ size │ created │ accessed │ modified
───┼────────────────────┼──────┼────────┼──────────┼───────────┼─────────────┼───────┼──────────┼──────────────┼─────────────┼─────────────
0 │ CODE_OF_CONDUCT.md │ File │ │ No │ rw-r--r-- │ josephlyons │ staff │ 3.4 KB │ 52 mins ago │ 52 secs ago │ 52 mins ago
1 │ CONTRIBUTING.md │ File │ │ No │ rw-r--r-- │ josephlyons │ staff │ 1.3 KB │ 52 mins ago │ 4 mins ago │ 4 mins ago
2 │ Cargo.lock │ File │ │ No │ rw-r--r-- │ josephlyons │ staff │ 113.3 KB │ 52 mins ago │ 52 mins ago │ 52 mins ago
3 │ Cargo.toml │ File │ │ No │ rw-r--r-- │ josephlyons │ staff │ 4.6 KB │ 52 mins ago │ 52 mins ago │ 52 mins ago
4 │ README.md │ File │ │ No │ rw-r--r-- │ josephlyons │ staff │ 15.8 KB │ 52 mins ago │ 1 min ago │ 1 min ago
5 │ TODO.md │ File │ │ No │ rw-r--r-- │ josephlyons │ staff │ 0 B │ 52 mins ago │ 52 mins ago │ 52 mins ago
6 │ crates │ Dir │ │ No │ rwxr-xr-x │ josephlyons │ staff │ 704 B │ 4 months ago │ 52 mins ago │ 52 mins ago
7 │ docs │ Dir │ │ No │ rwxr-xr-x │ josephlyons │ staff │ 192 B │ 5 months ago │ 52 mins ago │ 52 mins ago
8 │ src │ Dir │ │ No │ rwxr-xr-x │ josephlyons │ staff │ 128 B │ 5 months ago │ 1 day ago │ 1 day ago
9 │ target │ Dir │ │ No │ rwxr-xr-x │ josephlyons │ staff │ 160 B │ 5 days ago │ 5 days ago │ 5 days ago
───┴────────────────────┴──────┴────────┴──────────┴───────────┴─────────────┴───────┴──────────┴──────────────┴─────────────┴─────────────
```
```shell
> ls -a | where name =~ "yml"
──────────┬─────────────
name │ .gitpod.yml
type │ File
size │ 866 B
modified │ 1 month ago
──────────┴─────────────
```