Shell Programming and Scripting

I have to join(no other command is allowed) 3 files together. And im aware that i have to sort these files(file1 file2 file3) first before I can join them.

However i have to output these sorted files to some temporary file. i can't just do sort -n file1 > file1 or i get an empty file output. Is there a way to join 3 files without using a other files(temp files etc) other than the 3 files I'm using to join together.

The way im doing it requires the temp files. so in short it'd be like

Code:

join <arguments> file1 file2 | sort > temp1
sort file3 > temp2
join <arguments> temp1 temp2 > Output

Hi,

You can use sort command with option "o".It will sort the file1 and write the output in the same file.No need to create temp file.

Code:

sort file1 -o file1

oh... that should've been something i could've worked out myself -_-

Assuming the files are already sorted, you can do:

Code:

join file1 file2 | join - file3 >output