Slackomatic – Send Slack messages from the command line!

Phew, it’s been quite a while since I updated this thing! I’ll get back into throwing stuff up here pretty regularly (maybe!).

I’ve been working on a script which you can find at my github repo here:

It is a pretty comprehensive tool for sending messages to Slack using their API – pretty much every API option has been implemented.

You’ll first need to register a Slack webhook from here:

Then simply need to grab a copy and stick it on your linux machine then make it executable…

chmod +x slack

[I haven’t tested this but it might also work in Windows now that you can install Ubuntu in Windows 10 – after all it is just a bash script and has no real dependencies]

Run the script without any command line arguments to get usage instructions. At a minimum you have to pass a username (-u) and some text (-t) to display. And also the Webhook you just registered (-w) but I would recommend editing the script and setting the WEBHOOK variable at the very top of the script.

You can now send messages directly from the command line or incorporate into any scripts etc that you want to receive notifications from. I use it to let me know about completed downloads, backups finished, server reboots, etc.

Usage instructions are here for info…


usage: /usr/bin/slack OPTIONS

Basic messages simply show a message from a specified username.
    -u    Username ........ [REQUIRED] User/App to display that posts the message.
    -t    *Text ........... [REQUIRED] 'Basic' message text, shown above attachment content.
    -c    Channel ......... [Note 2] Specify Slack channel. If not defined the webhook's channel will be used (#notifications).
    -e    Emoji ........... [Note 7] Emoji image for sender, see:

Attachment messages include an additional 'attachment' displayed under the basic message detailed above.
    -T    Title ........... Title is displayed as larger, bold text near the top of a message attachment.
    -l    Title Link ...... [Note 8] Hyperlink for Title (must contain 'http' part).
    -m    *Message ........ The main text in a message attachment.
    -p    *Pretext ........ Text that appears above the message attachment block.
    -C    Color ........... [Note 3] Colour of vertical bar on left of attachment. See:
    -a    Author .......... Text to display as author's name at the top of attachment.
    -b    Author Link ..... [Note 8] Hyperlink for Author text (must contain 'http' part).
    -B    Author Img URL .. URL to image to display on left of Author text. Will be resized to 16x16.
    -F    *Footer ......... Text to be displayed in small font at the bottom of the attachment.
    -f    Footer Img URL .. URL to image to be displayed beside the footer. Will be resized to 16x16.
    -I    Image URL ....... [Note 4] URL to image to display below the attachment. Will be resized to max 360x500.
    -i    Thumbnail URL ... [Note 4] URL to image to display as thumb on right side of attachment. Will be scaled to 75x75.
    -q    Fallback ........ Basic text to display if the attachment can not be displayed on user's device.
    -P    Priority ........ [Note 6] Some pre-configured message formats.

    -w    Webhook ......... Set API Webhook variable within script (at very top) or pass one if not setting in script.
    -h    Help ............ Display this guidance.
    -x    Dry-run ......... Display payload to be sent to Slack but don't actually execute send command.

    1 ... When supplying values for the options above, use double quotes to contain the text. Remember to escape (\) any quotes
          within your submitted text.
    2 ... The following channels are available in my Slack workspace (as of April 2018):
          #notifications (default as using this channels webhook) ; #alert ; #backup ; #media_stack ; #monitor ; #system
    3 ... Colors (-C) are specified in hex values, lookup here:
          This script has several pre-defined colors built-in therefore the following can be specified as text instead of a hex value:
          green (#008000), orange (#FFA500), red (#FF0000), blue (#0000FF), purple (#800080), pink (#FFC0CB), yellow (#FFFF00)
    4 ... Both Image and Thumbnail can not be displayed in same message. Image will take precedence over thumnail if both are supplied.
    5 ... Any characters should be okay to be entered in any field but the following three characters must be substituted:
              > Replace the ampersand, &, with &amp;
              > Replace the less-than sign, < with &lt;
              > Replace the greater-than sign, > with &gt;
    6 ... A set of priorities (case-sensitive) have been defined in this script. Specify one of the following to apply a pre-defined 'template':
              > info : message prefix = 'INFO' ; color = blue ; emoji = :information_source: (blue 'i' sign)
              > success : message prefix = 'SUCCESS' ; color = green ; emoji = :heavy_check_mark: (green tick)
              > alert : message prefix = 'ALERT' ; color = red ; emoji = :warning: (yellow warning sign)
          Any of these pre-defined fields can be individually overridden by passing that cmd line option
    7 ... Some useful emojis: :film_frames:, :tv:, :iphone:, :computer:, :floppy_disk:, :file_folder:, :warning:,
          :no_entry:, :hourglass:, :heavy_check_mark:, :hankey:, :fire:, :inbox_tray:, :information_source:
    8 ... Links can also be email 'mailto's e.g.
    9 ... 'Fields' and 'Actions' can also be sent via command line but this functionality has not been implemented here.

    Fields tagged with a '*' above can have Slack's markup applied to their content. Supported options:
        > *bold*
        > _italic_
        > ~strikethrough~
        > `inline code` - ticks need to be escaped with '\'
        > ```embedded code``` - ticks need to be escaped with '\'


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