CODEWITHSUNDEEP
shell
dj199008
dj199008

Reputation: 1789

How to insert lines from one file in the middle of another file using shell scripts

I intend to copy some lines of a file to a specified location in another file using shell scripts. I only know a command:

cat A >> B

But, it only works for copying all lines of file A and paste them to the end file B. Instead, I want to insert content from file A in the middle of the file B.

Example

File A:

aaa
bbb
ccc
ddd

File B:

AAA
BBB
CCC

Then copy lines 2-3 of file A to the file B after line 2:

AAA
BBB
bbb
ccc
CCC

In other words, I want to insert some successive lines of a file into another file at any point. How can I do that?

Upvotes: 0

Views: 511

Answers (2)

Nachiket Kate
Nachiket Kate

Reputation: 8571

I am not sure about any command but I have workaround for it,

If you know line no at which you want to add something then why dont you use head and tail commands

suppose you want to aaa in your some file A at line no 3 A is like,

AAA

BBB

CCC

DDD

then 

head -n 2 > B   # this will copy first 2 lines 
echo "aaa" >> B # your desired string at line no 3
tail -n 2 >>B  # remaining lines into file

instead of tail you can try 

'sed 1,2d' A >> B

or 

awk 'NR>2' A >> B

for writing remaining lines to B

This can be used for smaller files but will be heavy for larger files

Upvotes: 2

Gene
Gene

Reputation: 46990

Well, if you have the standard Linux tools, you can say

paste -d "\n" A B

Upvotes: 0

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