Translate a .POT file using translate-shell (Shell script version)

translate_pot.sh

#!/usr/bin/env bash

# Translate a POT file using BASH and the translate-shell utility
# homebrew users might install translate-shell by entering
# brew install translate-shell
# Linux user might try the default package manager (dnf/apt-get)

[[ ${BASH_VERSINFO[0]} -lt 4 ]] &&
  echo "BASH VERSION MUST BE >= 4" &&
  exit 1

POT="$1"
EXT=${POT##*.}
FNM=${POT%.*}
OUT="$PWD/${FNM}_trans.po"

[[ ! -f $1 ]] &&
  echo -e "File not found: $1" &&
  exit 1

! [[ $EXT =~ 'pot'$ ]] &&
  echo -e "Only .pot extension supported : your file extension $EXT" &&
  exit 1

[[ -f $OUT ]] &&
  echo -e "File already existent !: $OUT" &&
  exit 1

POTC=$(cat $POT)
TPRG=$(which trans)
TOPT="-b -s en -t de"

[[ ! -x $TPRG ]] && echo -e "translate-shell binary not found: $TPRG" && exit 1

declare -a ARRAY
readarray -t ARRAY <<< $POTC
ARR_N=${#ARRAY[@]}
for (( i = 0; $i < $ARR_N; i=$((i + 1)) )); do
  NAME=${ARRAY[$i]}
  if [[ $NAME =~ "msgstr \"\"" ]]; then
    TRANS=${ARRAY[$((i - 1))]}
    [[ $TRANS =~ ^msgid[[:space:]]\"(.*)\"$ ]]
    STR=${BASH_REMATCH[1]}
    if [[ $STR ]]; then
      STR_T=$($TPRG $TOPT "$STR")
      echo "msgstr \"$STR_T\"" >> $OUT
    else
      echo "msgstr \"\"" >> $OUT
    fi
  else
    echo $NAME >> $OUT
  fi
done