Clipboard – Remove Trailing New Line to Prevent Terminal Execution

clipboardnewlines

Is there some way to run whatever you copy to the 'clipboard' through some sort of filter? Ideally to strip out the trailing newline from something you copy, so that it doesn't auto-run in the terminal?

This is what it looks like when I copy the test in question, and I sometimes forget this is a new line.
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Best Answer

Good modern terminals support bracketed paste: when you use the terminal's paste command, it sends special escape sequences around the clipboard content. If your shell supports bracketed paste, it'll paste the clipboard content including any control characters as-is, and in particular a trailing newline will not trigger the execution of the command.

Zsh ≥5.1 supports bracketed paste and has it on by default. Older versions can be taught. Bash ≥4.4 supports bracketed paste if you add set enable-bracketed-paste on to ~/.inputrc.

If your terminal or shell doesn't support bracketed paste, you could define a shell function that pastes without the trailing newline.

In zsh, the following command recalls the content of the clipboard, minus trailing newlines, and brings it up for editing (even if there are multiple lines):

print -z -- "`xsel -b`"

In bash, you can push the content of the clipboard minus trailing newlines to the history stack. After this, press Up to bring up the command for editing.

history -s -- "`xsel -b`"

Related Solutions

How to Share the Clipboard Between Bash and X11

Bash's clipboard is internal to bash, bash doesn't connect to the X server.

What you could do is change the meaning of M-w to copy the selection to the X clipboard¹ in addition to bash's internal clipboard. However bash's integration is pretty loose, and I don't think there's a way to access the region information or the clipboard from bash code. You can make a key binding to copy the whole line to the X clipboard.²

if [[ -n $DISPLAY ]]; then
  copy_line_to_x_clipboard () {
    printf %s "$READLINE_LINE" | xsel -ib
  }
  bind -x '"\eW": copy_line_to_x_clipboard'
fi

If you want to do fancy things in the shell, switch to zsh, which (amongst other advantages) has far better integration between the line editor and the scripting language.

if [[ -n $DISPLAY ]]; then
  x-copy-region-as-kill () {
    zle copy-region-as-kill
    print -rn -- "$CUTBUFFER" | xsel -ib
  }
  x-kill-region () {
    zle kill-region
    print -rn -- "$CUTBUFFER" | xsel -ib
  }
  zle -N x-copy-region-as-kill
  zle -N x-kill-region
  bindkey '\C-w' x-kill-region
  bindkey '\ew' x-copy-region-as-kill
fi

¹ _{Gnome doesn't specifically have a clipboard, this is general to X.}
² _{As of bash 4.1, there is a bug in the key parsing code: key sequences bound with bind -x may not be more than two characters long. I think bash 4.2 fixes some cases of longer prefixes but not all of them; I haven't researched the details.}

Shell – How to capture stdin to a variable without stripping any trailing newlines

The trailing newlines are stripped before the value is stored in the variable. You may want to do something like:

var=`cat; echo x`

and use ${var%x} instead of $var. For instance:

printf "%s" "${var%x}"

Note that this solves the trailing newlines issue, but not the null byte one (if standard input is not text), since according to POSIX command substitution:

If the output contains any null bytes, the behavior is unspecified.

But shell implementations may preserve null bytes.

Best Answer

Related Solutions

How to Share the Clipboard Between Bash and X11

Shell – How to capture stdin to a variable without stripping any trailing newlines

Related Question