list_slack_active_channels.sh

# Slack team内で最近発言されたチャンネルだけをリストアップするやつ
# channels.listのページングは何も考えてない。1000くらいなら取れるっぽい。

TOKEN='xoxp-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' #slack regacy|user|bot token
curl 'https://slack.com/api/channels.list?token='$TOKEN'&exclude_archived=true&exclude_members=true&limit=1000' > tmp
for row in `cat tmp | jq -r '.channels[] | .id +"," + .name'`
do 
  ch_id=`echo $row | cut -d',' -f 1`
  date_raw=`curl 'https://slack.com/api/channels.history?token='$TOKEN'&channel='$ch_id'&count=100' | \
    jq -r '[.messages[] | select(.subtype == 'null')][0] | .ts' | \ # find the last HUMAN-made post 
    sed 's/\..*$//'`
  if [[ "$date_raw" = 'null' ]]; then
    continue #no one (human) posted in this channel
  fi
  date_readable=`date -r $date_raw`

  echo "${date_raw},${date_readable},${row}"
done | sort -t',' -k1 -nr | cut -d',' -f'2,4' > result
rm tmp