[root@localhost ~]$ cat 1.txt
1. Database.
1. Database.
[root@localhost ~]$ cat 2.txt
2. Web.
2. Web.
[root@localhost ~]$ cat 3.txt
3. IT Architecture.
3. IT Architecture.
[root@localhost ~]$ cat 4.txt
4. Project.
4. Project.
- Vertical format: We can merge them by concatenating vertically.
- Horizontal format: we can merge them by pasting them horizontally.
[root@localhost ~]$ cat 1.txt 2.txt 3.txt 4.txt
1. Database.
1. Database.
2. Web.
2. Web.
3. IT Architecture.
3. IT Architecture.
4. Project.
4. Project.
[root@localhost ~]$ cat 1.txt 2.txt 3.txt 4.txt > all.txt
Descendingly ordered combination:
[root@localhost ~]$ cat 4.txt 3.txt 2.txt 1.txt
4. Project.
4. Project.
3. IT Architecture.
3. IT Architecture.
2. Web.
2. Web.
1. Database.
1. Database.
If there're too many files to be combined, you can use wild card to merge them. But you cannot control the order in this way. It's always ordered by ascending-alphabetic filenames.
[root@localhost ~]$ cat *.txt
1. Database.
1. Database.
2. Web.
2. Web.
3. IT Architecture.
3. IT Architecture.
4. Project.
4. Project.
You can control the combination order by inline listing. For example, descending alphabetic order:
[root@localhost ~]$ cat `ls -r *.txt`
4. Project.
4. Project.
3. IT Architecture.
3. IT Architecture.
2. Web.
2. Web.
1. Database.
1. Database.
An ascending modified time order:
[root@localhost ~]$ cat `ls -t *.txt`
3. IT Architecture.
3. IT Architecture.
1. Database.
1. Database.
4. Project.
4. Project.
2. Web.
2. Web.
[root@localhost ~]$ paste 1.txt 2.txt 3.txt 4.txt
1. Database. 2. Web. 3. IT Architecture. 4. Project.
1. Database. 2. Web. 3. IT Architecture. 4. Project.
[root@localhost ~]$ paste 1.txt 2.txt 3.txt 4.txt > all.txt
Please note that, the default delimiter of paste is a tab character between texts. You can change it into other characters (e.g. a white space or a new line) in this way:
[root@localhost ~]$ paste 1.txt 2.txt 3.txt 4.txt -d ' '
1. Database. 2. Web. 3. IT Architecture. 4. Project.
1. Database. 2. Web. 3. IT Architecture. 4. Project.
[root@localhost ~]$ paste 1.txt 2.txt 3.txt 4.txt -d 'n'
1. Database.
2. Web.
3. IT Architecture.
4. Project.
1. Database.
2. Web.
3. IT Architecture.
4. Project.
You can also control the combination order introduced in the first approach.