Refactor code style and add -s option that processing *.in files

mca.sh

@@ -4,20 +4,24 @@ set -e
 
 EXEC_NAME="$(basename -- "$0")"
 
-options="$(getopt -n "$EXEC_NAME" -s sh  -o hvfdxr -l help -l version -- "$@")"
-eval set -- "$options"
+USAGE="Usage: $EXEC_NAME [OPTION]... [MCA_NAME|MCA_JAR|MCA_DIR] [INPUT]..."
+VERSION="mca 1.0.0"
+
+OPTION="$(getopt -n "$EXEC_NAME" -s sh -o hvfdxrs -l help -l version -- "$@")"
+eval set -- "$OPTION"
 
 SCREEN_OPTS=
 REATTACH_ONLY=0
+SKIP_CONFIGURE=0
 
 while :; do
     case "$1" in
         -h|--help)
-            echo "Usage: $EXEC_NAME [-fdxr] [MCA_NAME|MCA_JAR|MCA_DIR] [--] [INPUT]…"
+            echo "$USAGE"
             exit
             ;;
         -v|--version)
-            echo "MCA 1.0.0"
+            echo "$VERSION"
             exit
             ;;
         -f)
@@ -32,6 +36,9 @@ while :; do
         -r)
             REATTACH_ONLY=1
             ;;
+        -s)
+            SKIP_CONFIGURE=1
+            ;;
         --)
             shift
             break
@@ -44,7 +51,8 @@ MCA_NAME=$1
 if [ -z "$MCA_NAME" ]; then
     MCA_DIR="$PWD"
     MCA_NAME="$(basename -- "$MCA_DIR")"
-elif echo "$MCA_NAME" | grep -qE '^\.{,2}/' && MCA_NAME="$(readlink -f -- "$MCA_NAME")"; then
+elif echo "$MCA_NAME" | grep -qE '^\.{,2}/' && \
+    MCA_NAME="$(readlink -f -- "$MCA_NAME")"; then
     if [ -d "$MCA_NAME" ]; then
         MCA_DIR="$MCA_NAME"
         MCA_NAME="$(basename -- "$MCA_DIR")"
@@ -56,45 +64,65 @@ else
     MCA_DIR="$HOME/mca/$MCA_NAME"
 fi
 
-command -v screen > /dev/null || { echo "$EXEC_NAME: screen not found" >&2; exit 2; }
+if ! command -v screen > /dev/null; then
+    echo "$EXEC_NAME: screen not found" >&2
+    exit 2
+fi
 
 if [ -n "$2" ]; then
     shift
     INPUT="$(echo "$*" | sed 's/"/\\\0/g')"
-    screen -S "$MCA_NAME" -X eval "stuff \"$INPUT\"\\015" > /dev/null || {
-        echo "$EXEC_NAME: no screen found" >&2
+    if screen -S "$MCA_NAME" -X eval "stuff \"$INPUT\"\\015" > /dev/null; then
+        exit 0
+    else
+        echo "$EXEC_NAME: $MCA_NAME: no such screen found" >&2
         exit 2
-    }
-    exit
+    fi
 fi
 
 MCA_SCREENRC_FILE="/etc/mca/screenrc"
-[ -r "$MCA_SCREENRC_FILE" ] || { echo "$EXEC_NAME: can't read $MCA_SCREENRC_FILE" >&2; exit 2; }
+if [ ! -r "$MCA_SCREENRC_FILE" ]; then
+    echo "$EXEC_NAME: can't read $MCA_SCREENRC_FILE" >&2
+    exit 2
+fi
 
-if screen -c "$MCA_SCREENRC_FILE" "-$SCREEN_OPTS"rS "$MCA_NAME" > /dev/null 2>&1; then
-    exit
+if screen -c "$MCA_SCREENRC_FILE" "-$SCREEN_OPTS"rS \
+    "$MCA_NAME" > /dev/null 2>&1; then
+    exit 0
 elif screen -S "$MCA_NAME" -X select . > /dev/null 2>&1; then
     echo "$EXEC_NAME: this screen has already been attached to someone" >&2
     exit 2
 fi
 
-[ "$REATTACH_ONLY" -eq 1 ] && { echo "$EXEC_NAME: $MCA_NAME: no such a screen was found" >&2; exit 2; }
+if [ "$REATTACH_ONLY" -eq 1 ]; then
+    echo "$EXEC_NAME: $MCA_NAME: no such screen found" >&2
+    exit 2
+fi
 
-[ -d "$MCA_DIR" ] || { echo "$EXEC_NAME: $MCA_DIR: not found" >&2; exit 2; }
+if [ ! -d "$MCA_DIR" ]; then
+    echo "$EXEC_NAME: $MCA_DIR: such directory not found" >&2
+    exit 2
+fi
 
 cd "$MCA_DIR"
 
 MCA_RC_FILE="$MCA_DIR/.mcarc"
 
-# this file is taken from a dynamic variable, so we cannot specify an explicit path to the file
+# this file is taken from a dynamic variable, so we cannot specify an explicit
+# path to the file.
 # shellcheck disable=SC1090
-# `--` is supported in dash
+# `--` is supported in dash.
 # shellcheck disable=SC2240
-[ -e "$MCA_RC_FILE" ] && . -- "$MCA_RC_FILE"
+if [ -e "$MCA_RC_FILE" ]; then
+    set -a
+    . -- "$MCA_RC_FILE"
+    set +a
+fi
 
 if [ -z "$PLATFORM" ]; then
     if [ -z "$MCA_JAR" ]; then
-        MCA_JAR="$(find "$MCA_DIR" -maxdepth 1 -type f -name \*.jar | head -1)"
+        MCA_JAR="$(find "$MCA_DIR" -maxdepth 1 \
+            -type f -name \*.jar | head -1)"
         [ -z "$MCA_JAR" ] && {
             echo "$EXEC_NAME: no jar found in $MCA_DIR" >&2
             exit 2
@@ -103,7 +131,8 @@ if [ -z "$PLATFORM" ]; then
 
     if [ -e "$MCA_JAR" ]; then
         PLATFORM="$(basename -- "$MCA_JAR")"
-        PLATFORM="$(echo "$PLATFORM" | tr '[:upper:]' '[:lower:]' | grep -oE '[a-z]+' | head -1)"
+        PLATFORM="$(echo "$PLATFORM" | tr '[:upper:]' '[:lower:]' | \
+            grep -oE '[a-z]+' | head -1)"
     else
         echo "$EXEC_NAME: $MCA_JAR: no such file" >&2
         exit 2
@@ -157,27 +186,41 @@ case "$PLATFORM" in
     custom)
         ;;
     *)
-        echo "$EXEC_NAME: invalid platform: $PLATFORM. Valid: \
-bungee, waterfall, velocity, minecraft, bukkit, craftbukkit, spigot, paper, custom" >&2
+        echo "$EXEC_NAME: invalid platform: $PLATFORM. Valid: bungee, \
+            waterfall, velocity, minecraft, bukkit, craftbukkit, spigot, \
+            paper, custom" >&2
         exit 2
         ;;
 esac
 
-[ -n "$JAVA_HOME" ] && [ -d "$JAVA_HOME/bin" ] && PATH="$JAVA_HOME/bin:$PATH"
+if [ -n "$JAVA_HOME" ] && [ -d "$JAVA_HOME/bin" ]; then
+    PATH="$JAVA_HOME/bin:$PATH"
+fi
 
-java -version > /dev/null 2>&1 || {
+if ! command -v java > /dev/null; then
     echo "$EXEC_NAME: unable to get Java version (is Java installed?)" >&2
     exit 2
-}
+fi
 
 [ -n "$MAX_MEMORY" ] && JVM_FLAGS="-Xmx$MAX_MEMORY $JVM_FLAGS"
 [ -n "$MIN_MEMORY" ] && JVM_FLAGS="-Xms$MIN_MEMORY $JVM_FLAGS"
 
 MCA_CMD="$(which java) -server $JVM_FLAGS -jar $MCA_JAR"
 
-# papermc prints uncolored text if the COLORTERM variable is set to `truecolor`
+if [ "$SKIP_CONFIGURE" -eq 0 ]; then
+    ENV_LIST="$(cut -d= -f1 < ./.mcarc | sed 's/^/$/g'))"
+    FILE_LIST="$(find . -name '*.in' -type f)"
+
+    echo "$FILE_LIST" | while read -r line; do
+        envsubst "$ENV_LIST" < "$line" > "${line%*.in}"
+    done
+fi
+
+# papermc prints uncolored text if the COLORTERM variable is set to
+# `truecolor`.
 export COLORTERM=
 
-# we don't quote $MCA_CMD because screen treats arguments after the second one as a command
+# we don't quote $MCA_CMD because screen treats arguments after the second one
+# as a command.
 # shellcheck disable=SC2086
 exec screen -c "$MCA_SCREENRC_FILE" "-$SCREEN_OPTS"S "$MCA_NAME" -- $MCA_CMD