Is there a more efficient way to write this for loop in bash?

Question

I have a for loop that downloads climate data and crops it to the extent of my study area. Technically it works, but I'm wondering if there is a more efficient approach than having the loop repeatedly try to make the directories.

I was thinking about nesting this loop inside one that calls a variable from an array and makes a directory for it, then runs gdal... but I'm not sure how that would work because the gdal lines are slightly different.

## INITIAL LOOP
for MM in 01 02 03 04 05 06 07 08 09 10 11 12 ; do 
    #download tmin data
    mkdir tmin
    cd tmin
    gdal_translate -projwin $ulx $uly $lrx $lry -co COMPRESS=DEFLATE -co ZLEVEL=9  /vsicurl/https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/climatologies/tmin/CHELSA_tmin10_${MM}_1979-2013_V1.2_land.tif  CHELSA_tmin10_${MM}_1979-2013_V1.2_land_crop.tif 
    cd ..
    #download precpitation data
    mkdir prec
    cd prec
    gdal_translate -projwin $ulx $uly $lrx $lry -co COMPRESS=DEFLATE -co ZLEVEL=9  /vsicurl/https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/climatologies/prec/CHELSA_prec_${MM}_V1.2_land.tif  CHELSA_prec_${MM}_V1.2_land_crop.tif 
    cd ..
    #download tmax data
    mkdir tmax
    cd tmax
    gdal_translate -projwin $ulx $uly $lrx $lry -co COMPRESS=DEFLATE -co ZLEVEL=9     /vsicurl/https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/climatologies/tmax/CHELSA_tmax10_${MM}_1979-2013_V1.2_land.tif CHELSA_tmax10_${MM}_1979-2013_V1.2_land_crop.tif 
    cd ..
done

#THOUGHTS
var_list=(tmin tmax prec) 

for var in ${var_list[@]} ; do
    mkdir $var
    cd $var
    for MM in 01 02 03 04 05 06 07 08 09 10 11 12 ; do 
        #download tmin data
        mkdir tmin
        cd tmin
        gdal_translate -projwin $ulx $uly $lrx $lry -co COMPRESS=DEFLATE -co ZLEVEL=9  /vsicurl/https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/climatologies/tmin/CHELSA_tmin10_${MM}_1979-2013_V1.2_land.tif  CHELSA_tmin10_${MM}_1979-2013_V1.2_land_crop.tif 
        cd ..
        #download precpitation data
        mkdir prec
        cd prec
        gdal_translate -projwin $ulx $uly $lrx $lry -co COMPRESS=DEFLATE -co ZLEVEL=9  /vsicurl/https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/climatologies/prec/CHELSA_prec_${MM}_V1.2_land.tif  CHELSA_prec_${MM}_V1.2_land_crop.tif 
        cd ..
        #download tmax data
        mkdir tmax
        cd tmax
        gdal_translate -projwin $ulx $uly $lrx $lry -co COMPRESS=DEFLATE -co ZLEVEL=9     /vsicurl/https://os.zhdk.cloud.switch.ch/envicloud/chelsa/chelsa_V1/climatologies/tmax/CHELSA_tmax10_${MM}_1979-2013_V1.2_land.tif CHELSA_tmax10_${MM}_1979-2013_V1.2_land_crop.tif 
        cd ..
    done
done

Answer 1

Assuming the last arg for the gdal_translate calls is a file you wish to create, and assuming this argument can include a relative path to said file (to be created), how about:

mkdir -p tmin tmax prec           # '-p' suppresses the 'directory already exists' message

for MM in {01..12}
do
    # no ned for 'cd' calls if gdal_translate can write to a relative path/file, eg:

    gdal_translate ... tmin/CHELSA_tmin10_${MM}_1979-2013_V1.2_land_crop.tif 
    gdal_translate ... prec/CHELSA_prec_${MM}_V1.2_land_crop.tif 
    gdal_translate ... tmax/CHELSA_tmax10_${MM}_1979-2013_V1.2_land_crop.tif 
done