bash – for loop through multiple directories and their files

March 10, 2022

I have 5 directories in the same path my_path/:

my_path/1951 
my_path/1952 
my_path/1953 
my_path/1954 
my_path/1955

Each directory contains a different number of netcdf files ending in .nc.

And I need to perform a CDO command by looping in each directory and files. The command below applies only to the first directory and files my_path/1951/*.nc:

for i in my_path/1951/*.nc
do
   cdo selyear,1951/1970 "$i" "$i"2
done

The command select years from the nc files in the directory starting from the year of the directory and ending 20 years later.

So for the second directory it will be:

for i in my_path/1952/*.nc
do
   cdo selyear,1952/1971 "$i" "$i"2
done

and for the third:

for i in my_path/1953/*.nc
do
   cdo selyear,1953/1972 "$i" "$i"2
done

etc…

Is there a way I can do everything with a unique for loop or nested for loop instead of repeating the for loop above for each directory?

>Solution :

Would you please try the following:

#!/bin/bash

for i in my_path/*/; do
    year=${i%/}; year=${year##*/}       # extract year
    year2=$(( year + 19 ))              # add 19
    for j in "$i"*.nc; do
        echo cdo "selyear,${year}/${year2}" "$j" "$j"2
    done
done

It outputs command lines as a dry run. If it looks good, drop echo and run.