Shell Programming and Scripting

file Name a.txt
abc    def
def    xyz
123   5678

file Name b.txt
abc def
def xyz
123 5678

file Name c.txt
a.txt:abc    def
a.txt:def    xyz
a.txt:123   5678
b.txt:abc def
b.txt:def xyz
b.txt:123 5678

awk 'BEGIN{print "file name","out.txt"}FNR>1{print FILENAME":"$0}' *.txt

grep . {a,b}.txt >c.txt

f="c.txt"; ( echo "file Name $f"; grep -v file {a,b}.txt ) >$f

$ awk 'BEGIN{print "file name","out.txt"}{$0=FILENAME":"$0}1' *.txt

file name out.txt
a.txt:abc    def
a.txt:def    xyz
a.txt:123   5678
b.txt:abc def
b.txt:def xyz
b.txt:123 5678

"file Name a.txt"

"file Name b.txt"

grep . {a,b}.txt >c.txt

# cat a.txt
abc    def
def    xyz
123   5678
# cat b.txt
abc def
def xyz
123 5678
# cat c.txt
cat: c.txt: Aucun fichier ou répertoire de ce type
# grep . {a,b}.txt >c.txt
# cat c.txt
a.txt:abc    def
a.txt:def    xyz
a.txt:123   5678
b.txt:abc def
b.txt:def xyz
b.txt:123 5678
#

awk 'BEGIN{$0=FILENAME":"$0}1' *.txt

grep '^' *.txt > output