Bash: add string to the end of the file without line break

sed '$s/$/yourText2/' list.txt > _list.txt_ && mv -- _list.txt_ list.txt

If your sed implementation supports the -i option, you could use:

sed -i.bck '$s/$/yourText2/' list.txt

With the second solution you'll have a backup too (with first you'll need to do it manually).

Alternatively:

ex -sc 's/$/yourText2/|w|q' list.txt

perl -i.bck -pe's/$/yourText2/ if eof' list.txt

Just use printf instead, since it does not print the new line as default:

printf "final line" >> file

Let's create a file and then add an extra line without a trailing new line. Note I use cat -vet to see the new lines.

$ seq 2 > file
$ cat -vet file
1$
2$
$ printf "the end" >> file
$ cat -vet file
1$
2$
the end

You can use the -n parameter of echo. Like this:

$ touch a.txt
$ echo -n "A" >> a.txt
$ echo -n "B" >> a.txt
$ echo -n "C" >> a.txt
$ cat a.txt
ABC

EDIT: Aha, you already had a file containing string and newline. Well, I'll leave this here anyway, might we useful for someone.

Related