replace last character in a line with sed

I am trying to replace the last character in a line with the same character plus a quotation m开发者_StackOverflow社区ark '

This is the sed code

 sed "s/\([A-Za-z]\)$/\1'/g" file1.txt > file2.txt

but does not work. Where is the error?

try:

sed "s/\([a-zA-Z]\)\s*$/\1\'/" file

This will replace the last character in the line followed by none or many spaces.

HTH Chris

It seems pointless to replace a character with itself, so try this: for lines ending with a letter, add a quote to the end:

sed "/[a-zA-Z]$/s/$/'/"

This does what you ask for:

sed "s/\(.\)$/\1'/" file1.txt > file2.txt

Your line only matches a line with a single character. Note that the s operation only takes effect if the line matches, not if only a subset of the line matches the regex.