concatenating similar files in a directory

Shell Programming and Scripting
1

Hi,
I am new in unix.
I have below requirement:
I have two files at the same directory location
File1.txt and File2.txt (just an example, real scenario we might have File2 and File3 OR File6 and File7....)

File1.txt has :

header1
record1
trailer1

File2.txt has:

header2
record2
trailer2

I want to keep File2.txt as below and delete the File1.txt.

File2.txt will have:

header2
record1
record2
trailer2

Can anyone please provide some help here.

2

You may do that in the following steps:

1. head -1 File2.txt > result.tmp
2. grep 'record1' File1.txt >> result.tmp
3. awk 'NR>1' File2.txt > result.tmp
4. mv result.tmp File2.txt

Kinda cumbersome, but this is what comes to my head at the first sight of your question.
I know this can be achieved more elegantly with SED, but SED is still strange to me.

3

With sed:

$ sed '/header/ a\'$(grep record f1)'' f2 > newfile
header2
record1
record2
trailer2

That a\ will append the text at the address /header/ . You could then mv newfile to f2 and sowith overwrite it. Then rm f1. If your sed supports the -i flag, you can directly edit f2 so you'd just remove f1 afterwards.

4

One caveat, does the trailer record have a count of the detail records.

5

The trailer does have a count of the records.

---------- Post updated at 01:00 PM ---------- Previous update was at 12:50 PM ----------

Thanks for all the replies....
first problem is to identify that which one is file created earlier and which one later. It could be file1 and file2 or file6 and file7....so on. I am writting this in a shell script. FILE_NAME=`echo File*` will give me
FILE_NAME=File1 File2.
I want to get it in seperate variable as below.
example:
FILE_NAME1=File1
FILE_NAME2=File2

so that i can use the logic suggested by all of you.