Replacing text with apostrophe text via sed in applescript - sed

Question

I have an applescript to find and replace a number of strings. I ran in the problem of having a replacement string which contained & some time ago, but could get around it by putting \& in the replacement property list. However an apostrophe seems to be far more annoying.
Using a single apostrophe just gets ignored (replacement doesn't contain it), using \' gives a syntax error (Expected “"” but found unknown token.) and using \' gets ignored again. (You can keep doing that btw, even number gets ignored uneven gets syntax error)
I tried replacing the apostrophe in the actual sed command with double quotes (sed "s…" instead of sed 's…'), which works in the command line, but gives a syntax error in the script (Expected end of line, etc. but found identifier.)
The single quotes mess with the shell, the double quotes with applescript.
I also tried '\'' as was suggested here and '"'"' from here.
Basic script to get the type of errors:
set findList to "Thats.nice"
set replaceList to "That's nice"
set fileName to "Thats.nice.whatever"
set resultFile to do shell script "echo " & fileName & " | sed 's/" & findList & "/" & replaceList & " /'"

Answer 1

Try:
set findList to "Thats.nice"
set replaceList to "That's nice"
set fileName to "Thats.nice.whatever"
set resultFile to do shell script "echo " & quoted form of fileName & " | sed \"s/Thats.nice/That\\'s nice/\""
or to stick to your example:
set findList to "Thats.nice"
set replaceList to "That's nice"
set fileName to "Thats.nice.whatever"
set resultFile to do shell script "echo " & quoted form of fileName & " | sed \"s/" & findList & "/" & replaceList & "/\""
Explanation:
The sed statement is usually enclosed by single quotes like this:
set myText to "Hello"
set xxx to do shell script "echo " & quoted form of myText & " | sed 's/ello/i/'"
However, in this example you could have exluded the single quotes altogether.
set myText to "Hello"
set xxx to do shell script "echo " & quoted form of myText & " | sed s/ello/i/"
The unquoted sed statement will break down as soon a space is included.
set myText to "Hello"
set xxx to do shell script "echo " & quoted form of myText & " | sed s/ello/i there/"
--> error "sed: 1: \"s/ello/i\": unterminated substitute in regular expression" number 1
Since you can't include an apostrophe within a single quoted statement (even if you escape it), you can enclose the sed statement in double quotes like this:
set myText to "Johns script"
set xxx to do shell script "echo " & quoted form of myText & " | sed \"s/ns/n's/\""
EDIT
Lauri Ranta makes a good point that if your find or replace string contains escaped double quotes my answer won't work. Her solution is as follows:
set findList to "John's"
set replaceList to "\"Lauri's\""
set fileName to "John's script"
set resultFile to do shell script "echo " & quoted form of fileName & " | sed s/" & quoted form of findList & "/" & quoted form of replaceList & "/"

Answer 2

I'd also use text item delimiters. You don't have to include AppleScript's in the default scope or set the property back if it isn't used later.
set input to "aasearch"
set text item delimiters to "search"
set ti to text items of input
set text item delimiters to "replace"
ti as text
There's no easy way to escape the search or replace patterns if they can contain something that would be interpreted by sed.
set input to "a[a"
set search to "[a"
set replace to "b"
do shell script "sed s/" & quoted form of search & "/" & quoted form of replace & "/g <<< " & quoted form of input
If you have to use regular expressions, scripting languages like Ruby have methods for creating patterns from strings.
set input to "aac"
set search to "(a+)"
set replace to "\\1b"
do shell script "ruby -KUe 'print STDIN.read.chomp.gsub(Regexp.new(ARGV[0]), ARGV[1])' " & quoted form of search & " " & quoted form of replace & " <<< " & quoted form of input without altering line endings