Common clipboard helpers

clip_do

#!/bin/sh -eu
param="${1:-help}"
# this 'implements' a echo "${param}" | head -1
# in order to avoid passing a multiline string to:
#  - command -V -- "${param}"
#  - eval "${param}"
# leading in possible executing of ${param}
param="${param%%
*}"
current="$(xclip -o -sel clip)"

into_clip() {
   xclip -i -sel clip
}

out_clip() {
   printf '%s' "${current}"
}

base64() {
   if out_clip | command base64 -d -i - >/dev/null 2>&1; then
      out_clip | command base64 -d -i - | into_clip
   else
      out_clip | command base64 - | into_clip
   fi
}

qrcode() {
   qrencode -o - -- "${current}" | feh --title float -
}

help() {
    cat <<EOF
requirements: qrencode, feh, xclip
${0##*/} <param>
   base64 # de- or encodes current clip to base64
   qrcode # outputs current clipboard as qrcode
EOF
}

if command -V -- "${param}" | grep -qse ".*is a shell function$"; then
   eval "${param}"
else
   help
   echo "Error: param ${param} not found!"
   exit 1
fi

Initial announcement on twitter.
PS: This is a successor of qrclip.

Hm, you might be able to create a ${param} that makes my grep always match, which would results in 'arbitrary' code eval.
It's so hard to shoot into your knee in Shell scripting :-).
Nevermind figured it's not necessary to include ${param} in my regex statement...
A for a moment it would have been possible to get this eval:
`command -V -- "$(printf this is a shell function\n;echo hello world)"

I've figured out I can fake a head -1 on param by doing such thing:

foo="$(printf 'This\nis\nno\nmore\nmultiline-string\n\rok')"
echo "${foo%%
*}"