Turn a single sed command into a reusable Textmate command

Question

I have 7 lines of text:

a
b
c
d
e
f
g

Now I want to add characters to the end of each line, to end up with:

a,
b,
c,
d,
e,
f,
g,

I found that I can use the "sed" command and run my selection through sed using "Filter through command" in Textmate

sed 's/$/,/'

Now, one question remains: how do I turn this into a Textmate command that takes input in some sort of way (so it knows what text to append)?

(My tries in doing this have proven unsuccessful)

Answer 1

Pop this into a command within the Text bundle, it'll append whatever is in the clipboard to the end of all lines that have been selected:

#!/bin/bash
if [[ $(pbpaste|wc -l) -eq 0 ]]
    then r=`pbpaste`
    sed 's/$/'$r'/'
    else sed 's/$/,/'
fi

It's currently limited to appending one line's worth of text, if the clipboard contains more than one line it will default to a comma at the end of the selected lines.

Edit:

To take this a little further, here's a version that provides a dialog box which prompts for the input of the string that will be appended to each line in the selection:

#!/bin/bash
r=$(CocoaDialog inputbox --title "String to be appended to EOL" \
   --informative-text "Enter string:" \
   --button1 "Okay" --button2 "Cancel")

[[ $(head -n1 <<<"$r") == "2" ]] && exit_discard

r=$(tail -n1 <<<"$r")

sed "s/$/$r/"

Answer 2

In Text menu there is already a command "Edit each line in selection" exactly do this. It will put cursor on first line and what you type there repeated on each line.