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Upload files and snippets to Slack chat from the command-line.

Getting started

Log in to your account and get your API token from

gem install slackcat
export SLACK_TOKEN=<your api token>
echo 'hello world' | slackcat -c <channel>

Note: since gem dependencies build extension modules, you may need ruby headers installed. For example, using system ruby on debian derivatives, you need to install the ruby-dev package.

Environment variables

  • SLACK_TOKEN: your token from
  • SLACK_CHANNEL: default destination channel; will be used if no -c, -g or -u option given

Command-line options

            --token, -k <s>:   Slack API token
         --channels, -c <s>:   Channels to share
           --groups, -g <s>:   Groups to share
            --users, -u <s>:   Users (DMs) to share
         --filetype, -t <s>:   File type identifier
            --title, -T <s>:   Title of file
         --filename, -n <s>:   Filename of file
  --initial-comment, -i <s>:   Initial comment to add
                 --post, -p:   Post instead of upload
            --multipart, -m:   Multipart upload each file
         --download, -d <s>:   Download a linked file
          --save-as, -s <s>:   Save downloaded file as
                 --help, -h:   Show this message

Basic usage: text snippets

To upload text snippets, slackcat is used similarly to unix cat: read data from STDIN or list filenames as arguments. Multiple files will be concatenated.


date | slackcat -c general
slackcat -u buddy foo.txt bar.txt

Uploads to slack are private by default. If you list channels, groups or usernames, content will be shared to them.

Multipart file uploads

If you wish to upload binary files, for example images, use the -m option, which will cause each file to be uploaded separately.


slackcat -c general -m kitten.jpg cat.gif

Slack does a good job of setting filetype correctly from mimetype, though you may override this with the -t option.

This mode does not read stdin.

Post messages as chat text

To post text as a normal chat, instead of as a text snippet, use the -p option.


date | slackcat -c general -p
slackcat -u buddy -p foo.txt bar.txt

Due to a limitation of the slack api you may also pass only one channel, group or username.

Example usage from vim

Upload contents of buffer:

:%! slackcat -c dev

Example usage from emacs

Upload contents of region:

M-| slackcat -c dev

To make a named function:

(setenv "SLACK_TOKEN" "<your api token>")

(defvar slackcat-bin  "slackcat" "Command to invoke slackcat.")
(defvar slackcat-args "-c dev"   "Default arguments to pass to slackcat.")

(defun slackcat (&optional b e)
  "Upload contents of region to slack chat."
  (interactive "r")
  (let ((args (read-from-minibuffer "slackcat args: " slackcat-args)))
    (shell-command-on-region b e (format "%s %s" slackcat-bin args))))


Upload files to Slack chat from the command-line.




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