Add file name as a new column with awk - awk

Question

First of all existing questions didn't solve my problem that's why I am asking again.
I have two txt files temp.txt
adam 12
george 15
thomas 20
and demo.txt
mark 8
richard 11
james 18
I want to combine them and add a 3rd column as their file names without extension, like this:
adam 12 temp
george 15 temp
thomas 20 temp
mark 8 demo
richard 11 demo
james 18 demo
I used this script:
for i in $(ls); do name=$(basename -s .txt $i)| awk '{OFS="\t";print $0, $name} ' $i; done
But it yields following table:
mark 8 mark 8
richard 11 richard 11
james 18 james 18
adam 12 adam 12
george 15 george 15
thomas 20 thomas 20
I don't understand why it gives the name variable as the whole table.
Thanks in advance.

Answer 1

Awk has no access to Bash's variables, or vice versa. Inside the Awk script, name is undefined, so $name gets interpreted as $0.
Also, don't use ls in scripts, and quote your shell variables.
Finally, the assignment of name does not print anything, so piping its output to Awk makes no sense.
for i in ./*; do
name=$(basename -s .txt "$i")
awk -v name="$name" '{OFS="\t";print $0, $name}' "$i"
done
As such, the basename calculation could easily be performed natively in Awk, but I leave that as an exercise. (Hint: sub(regex, "", FILENAME))

Answer 2

awk has a FILENAME variable whose value is the path of the file being processed, and a FNR variable whose value is the current line number in the file;
so, at FNR == 1 you can process FILENAME and store the result in a variable that you'll use afterwards:
awk -v OFS='\t' '
FNR == 1 {
basename = FILENAME
sub(".*/", "", basename) # strip from the start up to the last "/"
sub(/\.[^.]*$/, "", basename) # strip from the last "." up to the end
}
{ print $0, basename }
' ./path/temp.txt ./path/demo.txt
adam 12 temp
george 15 temp
thomas 20 temp
mark 8 demo
richard 11 demo
james 18 demo

Answer 3

Using BASH:
for i in temp.txt demo.txt ; do while read -r a b ; do printf "%s\t%s\t%s\n" "$a" "$b" "${i%%.*}" ; done <"$i" ; done
Output:
adam 12 temp
george 15 temp
thomas 20 temp
mark 8 demo
richard 11 demo
james 18 demo
For each source file read each line and use printf to output tab-delimited columns including the current source file name without extension via bash parameter expansion.

Answer 4

First, you need to unmask $name which is inside the single quotes, so does not get replaced by the filename from the shell. After you do that, you need to add double quotes around $name so that awk sees that as a string:
for i in $(ls); do name=$(basename -s .txt $i); awk '{OFS="\t";print $0, "'$name'"} ' $i; done