Why String concatenation of extracted file names does not work? - bash

Question

I have a file "a.txt", that contains file names with paths.
a.txt:
/root/chan/properties.lo
/root/attributes.cc
/root/chan/eagle/bath.ear
I would like to extract these file names and put them in one variable this way:
#!/bin/bash
for i in $(cat a.txt); do
o+=$(basename $i)
done
echo $o
But it does not work.
I am geting:
feedBackMailConfiguration.xmltiess
Please, help.

Answer 1

while read -r i;
do
o=$o" "$(basename $i)
done < a.txt
echo $o
The above will do it.
(edits for copy and paste errors)
More edits: just tried this (terminator, ubuntu) and it give the right result:
while read -r i; do o="$o $(basename $i)";done < a.txt

Answer 2

You just need to add a space concatenation to your script, like this:
#!/bin/bash
for i in $(cat a.txt); do
# Check the " " at the end of the following line
o+=$(basename $i)" "
done
echo $o
And it would work

Answer 3

"o+=..." is not really portable (which version of bash allows it? I never saw it until your mention of it? It looks like perl mechanisms)
Edit2 : following vladintok remarks on what the output is, I add DEBUG infos to try to pinpoints the problem
Edit3 : another step of trying to take out of the way every possible explanation for the weird output reported... I unalias, and unset any function named "o" and "basename" ...
Try:
#!/bin/bash
unalias o 2>/dev/null
unalias basename 2>/dev/null
unset o 2>/dev/null
unset basename 2>/dev/null
for i in $(cat a.txt); do
printf 'DEBUG: i is: %s\n' "$i"
o="${o} $(basename $i)"
done
printf 'DEBUG: final o is: %s\n' "$o"
echo $o
#end of the script.
(of course the above is a SINGLE file. Name it 'test.bash", make it executable: chmod +x test.bash, and then execute it : ./test.bash)
Edit1: I corrected the o=$o" "$(basename $i) into o="${o} $(basename $i)" as pointed out by Pantoine. Otherwise, toto=$toto" "titi : would assign to toto everything until the first space (which will be somewhere inside $toto, after the first iteration or if a basename contained spaces)...