Concatenation of 2 Files

[Pando]

I have 2 files which contains the same line item 1. During concatenation, i need to dispose of the line 1 from file2 and append the succeeding line to file1. Is there a way to do it in one command line?

Maximum points to all correct reply!

Thanks!

[Elmar P. Kolkman]

I'm not sure I understand the question correctly, but you could do something like this:
sed -n '2,$p' file2 >> file1

Of course there are lots of ways to do the cat without line 1...

[H.Merijn Brand (procura]

# man join

Enjoy, Have FUN! H.Merijn

[Muthukumar_5]

To remove first line of file2 then,

awk '{ if (NF!=1) print $0 }' file2 >> file1

If you want to remove duplicate lines in file2 compared to file1 then,

grep -vf file1 file2 >> file1

HTH.

[Elmar P. Kolkman]

I think Muthumumar meant NR in his awk syntax.

The grep is also dangorous. If file1 contains a line consisting of a part of a line of file2, those are skipped when adding file2.

Example: file1 contains 2 lines:
aaa
bba

file2 contains following lines:
aaaa
bbbb
bbba

Now only line 2 would be added with the grep...

If the resulting order is not important, a simpler solution would be in that case:
sort -u file1 file2 > file3

[Thierry Poels_1 · Accepted solution]

hi,

tail +2 file2 >> file1

good luck,
Thierry Poels.

[Kent Ostby]

If you want all the lines after line 1 then it would be:

awk 'NR>1{print $0}' file2 >> file1

for just the second line, it would be:

awk 'NR==2{print $0}' file2 >> file1

Oz

[James A. Donovan]

Maybe something like this is what you're looking for?

Given two files:

$ cat file1
aaa
bbb
ccc
ddd

$ cat file2
aaa
eee
fff

$ comm -13 file1 file2 >>file1

...this would append all lines that appear ONLY in file2 to the end of file1...

$ cat file1
aaa
bbb
ccc
ddd
eee
fff

...continuing the example...

$ cat file3
aaa
bbb
ccc
ggg

$ comm -13 file1 file3 >>file1

$ cat file1
aaa
bbb
ccc
ddd
eee
fff
ggg

...shows that since file3 and file1 both contain lines aaa, bbb and ccc, only line ggg from file3 is appended.

[Pando]

Thanks for all the replies. It was a big help!