I want to add numbers from two txt files. The number will change in file1, and file2 should update itself like this file2 = file1 + file2. Decimals not needed.
Example:
file1
3 file2
7 Output:
file1
3 file2
10 I tried $ paste file1 file2 | awk '{$0 = $1 + $2}' > file2 but all it does is copy the number from file1 to file2.
In-place replacements are not natively supported in awk. You can use sponge from moreutils to rewrite to a file you read in.
awk-way to add two files line-by-line
awk ' FNR==NR { a[NR]=$1 } FNR!=NR { print $1+a[FNR] }' file1 file2 | sponge file2 Simpler non-awk way, that also supports floating points:
paste -d'+' file1 file2 | bc -l | sponge file2 Both methods support multi-line files.
You could do this:
let tot=$(cat file1)+$(cat file2) echo $tot I have tried with command and it worked fine too
paste f1 f2| awk '{print $1+$2}' >f2_tmp && mv f2_tmp f2 praveen@praveen:~$ cat f1 3 praveen@praveen:~$ cat f2 10 praveen@praveen:~$ 