Author: ab

Using Terminal on macOS you may at some point have wondered about the small gray square brackets before the prompt. (There is also a counterpart closing bracket ‘]’ at the right side of Terminal window.)

They appeared first in Terminal in El Capitan (10.11). They are called ‘Marks’ and simplify scrolling through the output in the Terminal window.

By default, every command that is executed automatically gets marked.

Jump to the Mark

You can quickly scroll the Terminal output to previous marks (i.e. command prompts) with ⌘↑ (Command-Up Arrow) and to next mark with ⌘↓ (Command Down-Arrow). This allow you to quickly skip through the command prompts in your window.

Select Output

You can quickly select output between Marks. ⌘⇧↑ (Command-Shift-Up) will select the output up to, but not including the previous command prompt. ⌘⇧↓ (Command-Shift-Down) will select the output up to, but not including the next command prompt. When you repeatedly hit this key combo the selection will be extended further, including the intermittent command prompts.

⌘⇧A (Command-Shift-A) or ‘Select Between Marks’ from the ‘Edit’ menu, will select to the previous mark, if you are the last (empty) command prompt, otherwise it will select to the next mark.

Clearing Output

You can also just remove the output of the previous command with ‘Clear to Previous Mark’ from the ‘Edit’ menu (⌘L). This is less destructive than clearing the entire screen or buffer.

Marks and Bookmarks

Marks are very useful. However, they are all the same, so jumping back to a specific mark in your Terminal scroll buffer will get harder and harder you have to hit ⌘↑ more and more often.

You can elevate a mark to a bookmark, which will allow you to jump directly to it. Jump to the line you want to bookmark or select some text and choose ‘Mark as Bookmark’ from the ‘Edit’ menu (⌘⌥U) or context menu.

Bookmarks have a bolder vertical bar ‘|’ at the left and right edge of the window.

You can jump to previous and next bookmarks with ⌘⌥↑ and ⌘⌥↓, or you jump directly to a bookmark from the list in the ‘Edit’ > ‘Bookmark’ menu.

The ‘Edit’ > ‘Bookmarks’ menu also has ‘Insert Bookmark’ and ‘Insert Bookmark with Name…’ items. These will mark the current command prompt as a bookmark, and give you the option of naming the bookmark, rather than having the default timestamp as the name.

Terminal will set an automatic bookmark when restoring a Terminal window (after a reboot). This setting is controlled in the ‘Resume’ area in the ‘Window’ Tab of the Profiles area of the settings.

Not Leaving Marks

If the grey brackets indicating the marks annoy you, you can hide them with ‘Hide Marks’ from the ‘View’ menu. This will only hide the marks and bookmarks, they will still be automatically (or manually) created and you can still jump to them.

You can disable automatic mark creation entirely by deselecting ‘Automatically Mark Prompt Lines’ from the ‘Edit’ > ‘Marks’ submenu. When you have disabled automatic marking, you can execute and manually mark a prompt with ⌘↩︎ (Command-Return).

With automatic marking enabled, you can execute a command without marking with ⌘⇧↩︎ (Command-Shift-Return).

You can also manually remove a mark, by scrolling or jumping to it and choosing ‘Unmark’ from the ‘Edit’ > ‘Marks’ menu or the context menu.

Marking Spots Programatically

I have added the following aliases to my .bash_profile:

alias mark="osascript -e 'if app \"Terminal\" is frontmost then tell app \"System Events\" to keystroke \"u\" using command down'"
alias bookmark="osascript -e 'if app \"Terminal\" is frontmost then tell app \"System Events\" to keystroke \"M\" using command down'"

This way I can put the mark in between two commands and just let them run:

$ system_profiler SPApplicationsDataType; mark; system_profiler SPExtensionsDataType

The downside of this approach that the aliases do not work when Terminal is in the background.

Continuing in my informal series of Terminal articles, I’d like to visit two tools that help interact from the shell to a particular part of the macOS UI: the clipboard.

The clipboard is the ‘place’ where macOS stores anything you cut (⌘X) or copy (⌘C). Later the system reads from the clipboard (and possibly converts the data) when you paste (⌘V).

Terminal can trivially interact with the clipboard. You can select text in the Terminal and copy it, and then paste it elsewhere, you can also paste text in the command prompt itself.

(This is useful when you read a great iBook with many Terminal commands. You can simply copy the command from the iBook text and paste into Terminal.)

There are however, two commands, specific to macOS that connect the clipboard closer to other shell commands.

pbcopy will take the contents of stdin (usually text, but could be any stream of data) and put them in the clipboard. So, anything you pipe into pbcopy will end up in the clipboard, so you can paste it into a different application.

(NeXTSTEP was the operating system that Mac OS X was originally based on. What was called the ‘clipboard’ in Mac OS was called ‘pasteboard’ in NeXTSTEP. While all references visible to the user where changed to the Mac OS naming, you still find the old NeXTSTEP names in the ‘innards’ of macOS, hence pbcopy and pbpaste.)

Examples:

# easier than open, select all, copy
$ cat ideas.txt | pbcopy

# converts Word Doc to plain text and puts it in the clipboard
$ textutil -convert txt MyBook.docx -stdout | pbcopy

$ ipconfig getifaddr en0 | pbcopy

$ system_profiler SPHardwareDataType SPSoftwareDataType | pbcopy

$ uuidgen | pbcopy

I use the last command a lot when I need UUIDs for custom configuration profiles. It is much easier to pipe the output directly into the clipboard, than to select and copy the output.

One downside of this it, that you cannot see what is piped into the clipboard. You can easily make the new clipboard contents visible by typing pbpaste as the next command:

$ uuidgen | pbcopy
$ pbpaste
A524B454-5B42-4832-943D-896DF755FDEC

or

$ uuidgen | pbcopy; pbpaste
95DC9C0E-052E-4896-A4D3-1BB5EAECD93C

(Several UUIDs were wasted writing this article.)

pbpaste is the counterpart to pbcopy. pbpaste will take the contents of the clipboard, and if they are plain text write them to stdout. That alone can be useful when you want to visualize the clipboard but gets more powerful when you pipe or substitute it into other unix commands.

Examples:

# after copying the output of uuidgen
$ plutil -replace PayloadUUID -string $(pbpaste) MyConfigProfile.mobileconfig

# copy an html snippet from somewhere or
$ echo '<a href="https://scriptingosx.com">Scripting OS X</a>' | pbcopy
# then
$ pbpaste | textutil -stdin -format html -convert rtf -stdout | pbcopy

This last command will convert an HTML snippet into rich text (rtf).