How to extract substring in Fish shell?

Question

I got the following variable:

set location "America/New_York"

and want to display only the part before the / (slash) using fish shell syntax.

America

Using bash, I was simply using a parameter expansion:

location="America/New_York"
echo ${location##*/}"

Question

How do I do that in a fish-way?

faho · Accepted Answer · 2019-05-21T16:03:31.970

17

Since fish 2.3.0, there's a builtin called string that has several subcommands including replace, so you'll be able to do

string replace -r "/.*" "" -- $location

or

set location (string split "/" -- $location)[1]

Alternatively, external tools like cut, sed or awk all work as well.

edited May 21 '19 at 16:03

answered Dec 09 '15 at 21:14

faho

What if we care about both return values? Storing them in a list works, but is there a way to store them into more specific vars straight away? E.g. `set a, b (string split / foo/bar)` – Dennis May 16 '17 at 20:59
maybe you could add a link to the docs, and find out/mention what's the first version that supports `string replace`? – myrdd May 21 '19 at 10:49
2.3 (which was released after that answer was written, so there were no docs to link to), http://fishshell.com/docs/current/commands.html#string. – faho May 21 '19 at 16:01

score 3 · Answer 2 · answered Dec 09 '15 at 20:18

3

A possible solution is to use cut but, that look hackish:

set location "America/New_York"
echo $location|cut -d '/' -f1

America

answered Dec 09 '15 at 20:18

Édouard Lopez

2

Part of the fish philosophy is to have as small a feature set as possible. fish does not do parameter expansion like bash with `${location%%/*}`. This answer is the fish way. From the [Design document](http://fishshell.com/docs/current/design.html): "Everything that can be done in other shell languages should be possible to do in fish, though fish may rely on external commands in doing so." – glenn jackman Dec 09 '15 at 21:15

score 2 · Answer 3 · answered Jun 09 '21 at 11:49

Use the field selector -f of string split

> string split / "America/New_York" -f1
America

and accordingly:

set location (string split / "America/New_York" -f1)

Sidenote: For the latter string involving multiple slashes, I don't know anything better than the cumbersome -r -m1 -f2:

> string split / "foo/bar/America/New_York" -r -m1 -f2
New_York