Search for text in table column by clicking on the column name

[moritzdietz]

I have spend at least 3 hours today reading the changelogs as well as the man page to see if I can get it to work but I am stumped, so here we go.

I want to recreate the example from https://junegunn.github.io/fzf/releases/0.59.0/#click-header-enhancements where I have tabular input and be able to click on each column and be able to search for strings within this column.

I have JSON which looks like this:

[
  {
    "certname": "node1.contoso.com",
    "title": "Role::Db::Oracle"
  },
  {
    "certname": "node2.contoso.com",
    "title": "Role::Test"
  },
  {
    "certname": "node3.contoso.com",
    "title": "Role::Db::Oracle"
  }
]

I use this combination to format the output for fzf

❯ echo '[{"certname":"node1.contoso.com","title":"Role::Db::Oracle"},{"certname":"node2.contoso.com","title":"Role::Test"},{"certname":"node3.contoso.com","title":"Role::Db::Oracle"}]' | \
jq -r 'map(.certname + ";" + (.title | ascii_downcase)) | join("\n")' | \
column --table --separator ";" --table-columns Name,Role

this produces the following output:

Name               Role
node1.contoso.com  role::db::oracle
node2.contoso.com  role::test
node3.contoso.com  role::db::oracle

I borrowed and adapted a fzf command like so:

fzf --header-lines 1 \
  --header-border bottom --no-list-border --delimiter " " --accept-nth 1 \
  --color fg:dim,nth:regular \
  --bind 'click-header:transform-nth(
            echo $FZF_CLICK_HEADER_NTH
          )+transform-prompt(
            echo "$FZF_CLICK_HEADER_WORD> "
          )'

The complete command to try out looks like this:

echo '[{"certname":"node1.contoso.com","title":"Role::Db::Oracle"},{"certname":"node2.contoso.com","title":"Role::Test"},{"certname":"node3.contoso.com","title":"Role::Db::Oracle"}]' | \
jq -r 'map(.certname + ";" + (.title | ascii_downcase)) | join("\n")' | \
column --table --separator ";" --table-columns Name,Role | \
fzf --header-lines 1 \
  --header-border bottom --no-list-border --delimiter " " --accept-nth 1 \
  --color fg:dim,nth:regular \
  --bind 'click-header:transform-nth(
            echo $FZF_CLICK_HEADER_NTH
          )+transform-prompt(
            echo "$FZF_CLICK_HEADER_WORD> "
          )'

now while this produces output I can filter, it starts to break when I click on any of the column names to filter for the text within this column.

Can someone give me some pointers what I am doing wrong?

Additionally: I've read over and over things like "-nth". What does "-nth" even mean. For example I use accept-nth 1 already as I knew it would be the first thing from the entire string. But in other parts of fzf I don't understand it.

[junegunn]

I haven't looked closely enough but given that there are multiple consecutive spaces in the input, --delimiter " " seems wrong.

# Without --delimiter, fzf splits input into fields in awk-style.
echo '1st     2nd     3rd' | fzf --nth 2 --query 2

# No match.
# With a single space character as the delimiter, consecutive spaces are now recognized as a series of empty fields,
# --nth 2 points to one of the empty fields
echo '1st     2nd     3rd' | fzf --nth 2 --query 2 --delimiter ' '

Try removing it from your commands. If you really must use --delimiter, you can specify a regular expression,

echo '1st     2nd     3rd' | fzf --nth 2 --query 2 --delimiter ' +'

But I don't recommend it in this case, as it's unnecessary and it only makes the processing slower.

[moritzdietz]

Ok, so when you do:

echo 'Name               Role
node1.contoso.com  role::db::oracle
node2.contoso.com  role::test
node3.contoso.com  role::db::oracle' | fzf --header-lines 1 --accept-nth 1 --nth 2

or with --nth 1 it searches the correct column.

But this doesn't explain why the ps -ef example with clickable column names from the release notes doesn't work anymore -> which I want to recreate for my column names.

I kept adding complexity to the original question:

echo 'Name               Role
node1.contoso.com  role::db::oracle
node2.contoso.com  role::test
node3.contoso.com  role::db::oracle' | fzf --header-lines 1 --accept-nth 1 --nth 1 --color fg:dim,nth:regular --header-first --header-border --header="" --bind 'click-header:transform-nth(
            echo $FZF_CLICK_HEADER_NTH
          )+transform-prompt(
            echo "$FZF_CLICK_HEADER_WORD> "
          )+transform-header(echo ${FZF_CLICK_HEADER_NTH:-N/A})'

Here's a video of my confusion of the value of $FZF_CLICK_HEADER_NTH

example-3.mp4

[junegunn]

It looks like a bug that only affects the --reverse layout (which you seem to have it in your $FZF_DEFAULT_OPTS).

I'll look into it.

[moritzdietz]

Ah! Good point, I should've checked all the environment variables to make it more obvious how it's set.

echo $FZF_DEFAULT_OPTS
-m --height=50% --border --layout=reverse --inline-info --ansi --tabstop=4  --preview-window=wrap:hidden --bind=ctrl-r:toggle-preview --header 'Press CTRL-R to toggle display' --preview 'bat -A --line-range :500 --wrap=character --style=numbers --color=always {} || head -500 {}'

Thank's for taking the time!

[junegunn]

Okay, I see what's happening. Try this one, and you'll see it works as expected:

echo 'Name               Role
node1.contoso.com  role::db::oracle
node2.contoso.com  role::test
node3.contoso.com  role::db::oracle' | fzf --header-lines 1 --accept-nth 1 --nth 1 --color fg:dim,nth:regular --header-first --header-border --bind 'click-header:transform-nth(
            echo $FZF_CLICK_HEADER_NTH
          )+transform-prompt(
            echo "$FZF_CLICK_HEADER_WORD> "
          )+transform-footer(echo ${FZF_CLICK_HEADER_NTH:-N/A})'

In your command, by using transform-header, you're effectively prepending a number to the header section. It starts with:

Name     Role

But when you click Name, it becomes

1
Name     Role

And now, Name is not the first, but the second word in the combined header.

[moritzdietz]

Yes, I can confirm it works now. However like you said I had to remove --layout=reverse string from my ENV var.
Then I could see:

A.) That the fzf command starts so that I can search all columns -> all columns and text are white and not dimmed
B.) That the header section now correctly prints either 1, 2.. (note the "..") or N/A
C.) That I can click each column name and only search within this column and the other column gets dimmed

Originally:

FZF_DEFAULT_OPTS=-m --height=50% --border --layout=reverse --inline-info --ansi --tabstop=4  --preview-window=wrap:hidden --bind=ctrl-r:toggle-preview --header 'Press CTRL-R to toggle display' --preview 'bat -A --line-range :500 --wrap=character --style=numbers --color=always {} || head -500 {}'

I just removed --layout=reverse.

[moritzdietz]

The more I am looking into this, the more am I confused.

I boiled it down to this:

export FZF_DEFAULT_OPTS="--header 'Press CTRL-R to toggle display'"

echo 'Name               Role
node1.contoso.com  role::db::oracle
node2.contoso.com  role::test
node3.contoso.com  role::db::oracle' | fzf --header-lines 1 --accept-nth 1 --nth 1 --color fg:dim,nth:regular --header-first --header-border --bind 'click-header:transform-nth(
            echo $FZF_CLICK_HEADER_NTH
          )+transform-prompt(
            echo "$FZF_CLICK_HEADER_WORD> "
          )'

So I think the fact I have a --header defined in the default ops env variable and simultaneously using --header-lines 1 as well as --layout reverse results in the nth logic counting each word from Press CTRL-R to toggle display which is 5 words. At the same time the words from the input Name and Role have the value 6 and 7. All this makes the other logic break.

The reason I included transform-header(echo ${FZF_CLICK_HEADER_NTH:-N/A}) was to debug what was happening.
You suggested transform-footer(echo ${FZF_CLICK_HEADER_NTH:-N/A}) instead. So I removed it.

Now, the final solution with your help to all of this, is the following:

export FZF_DEFAULT_OPTS=""

echo 'Name               Role
node1.contoso.com  role::db::oracle
node2.contoso.com  role::test
node3.contoso.com  role::db::oracle' | fzf --layout reverse --header-lines 1 --accept-nth 1 --nth 1 --color fg:dim,nth:regular --header-border --bind 'click-header:transform-nth(
            echo $FZF_CLICK_HEADER_NTH
          )+transform-prompt(
            echo "$FZF_CLICK_HEADER_WORD> "
          )'

I'm posting this in case someone else stumbles across this in their search for help with this kind of issue :D