how to merge two files consistently line by line

Question

I have two files (file1.txt & file2.txt ) , files are only examples .

How to merge the two files , in order to create the file - merge_files.txt as example 3

I writing now ksh script , so merge can be done with ksh,awk,sed,perl one liner ...etc

Background - why I need to merge the files : my target is to rename the OLD file (exist in first field) to NEW file (exist in second field) ,

example1

more file1.txt

/etc/port1-192.9.200.1-255.555.255.0
/etc/port2-192.9.200.1-255.555.255.0
/etc/port3-192.9.200.1-255.555.255.0
/etc/port4-192.9.200.1-255.555.255.0
/etc/port5-192.9.200.1-255.555.255.0
.
.
.
.

example2

more file2.txt

/etc/port1-192.90.2.1-255.555.0.0
/etc/port2-192.90.2.1-255.555.0.0
/etc/port3-192.90.2.1-255.555.0.0
/etc/port4-192.90.2.1-255.555.0.0
/etc/port5-192.90.2.1-255.555.0.0
.
.
.
.

example3

 more merge_files.txt



 /etc/port1-192.9.200.1-255.555.255.0  /etc/port1-192.90.2.1-255.555.0.0
 /etc/port2-192.9.200.1-255.555.255.0  /etc/port2-192.90.2.1-255.555.0.0
 /etc/port3-192.9.200.1-255.555.255.0  /etc/port3-192.90.2.1-255.555.0.0
 /etc/port4-192.9.200.1-255.555.255.0  /etc/port4-192.90.2.1-255.555.0.0
 /etc/port5-192.9.200.1-255.555.255.0  /etc/port5-192.90.2.1-255.555.0.0
 .
 .
 .
 .
 .

example4 (merge_files.txt structure)

 first field                           second field

 OLD file                              NEW file

Answer 1

You can use paste to format the files side by side:

$ paste -d" " file1.txt file2.txt
/etc/port1-192.9.200.1-255.555.255.0 /etc/port1-192.90.2.1-255.555.0.0
/etc/port2-192.9.200.1-255.555.255.0 /etc/port2-192.90.2.1-255.555.0.0
/etc/port3-192.9.200.1-255.555.255.0 /etc/port3-192.90.2.1-255.555.0.0
/etc/port4-192.9.200.1-255.555.255.0 /etc/port4-192.90.2.1-255.555.0.0
/etc/port5-192.9.200.1-255.555.255.0 /etc/port5-192.90.2.1-255.555.0.0

E.g.:

$ paste -d" " file1.txt file2.txt | while read from to; do echo mv "${from}" "${to}"; done
mv /etc/port1-192.9.200.1-255.555.255.0 /etc/port1-192.90.2.1-255.555.0.0
mv /etc/port2-192.9.200.1-255.555.255.0 /etc/port2-192.90.2.1-255.555.0.0
mv /etc/port3-192.9.200.1-255.555.255.0 /etc/port3-192.90.2.1-255.555.0.0
mv /etc/port4-192.9.200.1-255.555.255.0 /etc/port4-192.90.2.1-255.555.0.0
mv /etc/port5-192.9.200.1-255.555.255.0 /etc/port5-192.90.2.1-255.555.0.0

Of course you would want to throw in some safety checks ([ -f "${from}" ], ...).

Disclaimer: Works only if there are no spaces in your filenames.

Answer 2

This Perl one-liner will display the renames necessary

perl -e 'open $f[$_-1], "file$_.txt" for 1,2; print "rename @n\n" while chomp(@n = map ''.<$_>, @f)'

If this works for you then replace the print statement with a real rename and use

perl -e 'open $f[$_-1], "file$_.txt" for 1,2; rename @n while chomp(@n = map ''.<$_>, @f)'

to do the actual renaming

Answer 3

paste -d " " file1.txt file2.txt

Works great for this job. But in case you are handling text files in a Windows environment and make use of GNU paste, make sure to transform the files to Unix format (CR) and not use files with (CR-LF).

GNU paste does not seem to handle DOS formats properly and parsing is unpredictable, the expected output is erratic and unexpected without warnings.

You may use GVIM to transform them easily (Edit/File Settings/File Format)

Answer 4

Completely unrelated ways to achieve the OP's goal of renaming numbered files:

for f in {1..5}; do mv /etc/port$d-192.9.200.1-255.555.255.0 /etc/port$d-192.90.2.1-255.555.0.0; done

Another possibility based on rename

rename 's/192.9.200.1/192.90.2.1/' /etc/port[1-5]-192.9.200.1-255.555.255.0

Answer 5

command

paste file1 file2

output

/etc/port1-192.9.200.1-255.555.255.0    /etc/port1-192.90.2.1-255.555.0.0
/etc/port2-192.9.200.1-255.555.255.0    /etc/port2-192.90.2.1-255.555.0.0
/etc/port3-192.9.200.1-255.555.255.0    /etc/port3-192.90.2.1-255.555.0.0
/etc/port4-192.9.200.1-255.555.255.0    /etc/port4-192.90.2.1-255.555.0.0
/etc/port5-192.9.200.1-255.555.255.0    /etc/port5-192.90.2.1-255.555.0.0