CODEWITHSUNDEEP
linuxbashtextmerge
user3891747
user3891747

Reputation: 89

merge two text files using bash scripts in linux

I have two text files. the first one looks like this: 

a  
b  
c

another file looks like this: 

1 2   
3 4

I want to use bash scripts in Linux to merge these two files so that each row of the first file will be placed next to all the rows of the second file and output looks like this: 

a 1 2    
a 3 4  
b 1 2  
b 3 4  
c 1 2  
c 3 4

Any help would be appreciated

Upvotes: 1

Views: 430

Answers (4)

boardrider
boardrider

Reputation: 6185

I'd probably be downvoted mercilessly, but I believe that these kind of tasks are better suited to Perl or Python.
Here's a Python 2 solution:

$ cat 1col.tmp
a
b
c

$ cat 2col.tmp
1 2
3 4

$ cat merge.py
with open("1col.tmp") as col1f:
    for c1 in col1f.readlines():
        with open("2col.tmp") as col2f:
            for c2 in col2f.readlines():
                print c1.strip(), c2.strip()

$ python merge.py
a 1 2
a 3 4
b 1 2
b 3 4
c 1 2
c 3 4

Upvotes: 0

RavinderSingh13
RavinderSingh13

Reputation: 133458

try one more awk where it will give output in same order as Input_file1.

awk 'FNR==NR{a[++i]=$0;next} {c[++k]=$0} END{for(q=1;q<=i;q++){for(u=1;u<=k;u++){print a[q],c[u]}}}'  Input_file1  Input_file2

Upvotes: 0

Petr Skocik
Petr Skocik

Reputation: 60058

In pure shell, you can simply do:

#Usage: the_script FirstFile SecondFile
while read -r l1; do
    while read -r l2 ; do
        echo "$l1 $l2"
    done <"$2"
done <"$1"

but the files better not be large, because the shell reads aren't very efficient (they make a syscall for each byte).

Upvotes: 1

anubhava
anubhava

Reputation: 784998

You can use awk like this:

awk 'NR==FNR{a[++n]=$0; next} {for (i in a) print $0, a[i]}' file2 file1

a 1 2
a 3 4
b 1 2
b 3 4
c 1 2
c 3 4

Reference: Effective AWK Programming

Upvotes: 3

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