Well yes, there is a smarter way to do this! And it's so easy you start wondering why you didn't think of this 160*4 translated sentences earlier (...)
Using AWK or GNU AWK (gawk) you can quickly select the correct columns and output a new CSV file with just the first (original) column and the correct language column.
It works like this:
awk -F "," '{print $1 "," $3}' source.csv > output.csv
-F "," = use "," as field separator.
{print $1 "," $3} = output the first field $1, then "," followed by the 3rd field $3.
source.csv > output.csv = your source and your output files.
In my case I use these lines as a shell script in my build tool to generate the correct translation files:
awk -F "," '{print $1 "," $2}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/en_EN/translate.csv
awk -F "," '{print $1 "," $3}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/nl_NL/translate.csv
awk -F "," '{print $1 "," $4}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/de_DE/translate.csv
awk -F "," '{print $1 "," $5}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/es_ES/translate.csv
HOWEVER If you have fields with commas in your translations ("Order today, enjoy tomorrow") you'll be out of luck with regular awk. You'll need GNU awk as this version is able to use smarter regex patterns as field separator.
If you're on a mac like I am, installation of GNU awk is easy if you already have homebrew installed on your mac: brew install gawk should do the trick.
instead of -F "," your field separator will look like -vFPAT='[^,]*|"[^"]*"' so the command looks like this:
gawk -vFPAT='[^,]*|"[^"]*"' '{print $1 "," $3}' source.csv > output.csv
As my translations contained commas in the fields I ended up using gawk and it looks like this:
gawk -vFPAT='[^,]*|"[^"]*"' '{print $1 "," $2}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/en_EN/translate.csv
gawk -vFPAT='[^,]*|"[^"]*"' '{print $1 "," $3}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/nl_NL/translate.csv
gawk -vFPAT='[^,]*|"[^"]*"' '{print $1 "," $4}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/de_DE/translate.csv
gawk -vFPAT='[^,]*|"[^"]*"' '{print $1 "," $5}' ./src/locale/theme_translations.csv > ./dist/app/design/frontend/foundation/default/locale/es_ES/translate.csv