Shell Programming and Scripting

awk 'code' file file file file

awk 'code' 4xfile

$ cat test
1
2
3
4
5
6
7

$ awk 'FNR==NR{print $0;next}{print "yes"$0}' $(seq -s "test " 3 | tr -d '[:digit:]')
1
2
3
4
5
6
7
yes1
yes2
yes3
yes4
yes5
yes6
yes7

$ awk 'FNR==NR{print $0;next}{print "yes"$0}' $(printf 'test %.0s' {1..2})
1
2
3
4
5
6
7
yes1
yes2
yes3
yes4
yes5
yes6
yes7

FILENAME="a"
LOOPS=4
while [ $loops -gt 0 ]
do
        FILES="$FILES $FILENAME"
        let LOOPS=LOOPS-1
done

awk '{...}' $FILES

awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' file file

awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' file{,}

awk 'code' file file file file

awk 'code' file{,,,}

$ echo file{,,,}
file file file file

$