Code cleaning using shellexec and add pre-commit hook

.pre-commit-config.yaml

@@ -13,13 +13,17 @@ repos:
           - --ignore-regex=.*codespell-ignore$
           # - --write-changes # Uncomment to write changes
         exclude_types: [csv, json]
-  - repo: https://github.com/adrienverge/yamllint
-    rev: v1.32.0
-    hooks:
-      - id: yamllint
-        ignore: .github/
   - repo: https://github.com/pre-commit/mirrors-prettier
     rev: v2.7.1
     hooks:
       - id: prettier
         args: ["--print-width", "100"]
+  - repo: https://github.com/adrienverge/yamllint
+    rev: v1.32.0
+    hooks:
+      - id: yamllint
+        ignore: .github/
+  - repo: https://github.com/shellcheck-py/shellcheck-py
+    rev: v0.10.0.1
+    hooks:
+      - id: shellcheck

check_pg_streaming_replication

@@ -49,7 +49,7 @@ DEBUG=0
 
 function usage () {
     ERROR="$1"
-    [ -n "$ERROR" ] && echo -e "$ERROR\n"
+    [[ -n "$ERROR" ]] && echo -e "$ERROR\n"
     cat << EOF
 Usage: $0 [-d] [-h] [options]
     -u pg_user              Specify local Postgres user (Default: try to auto-detect or use $DEFAULT_PG_USER)
@@ -74,11 +74,10 @@ Usage: $0 [-d] [-h] [options]
     -d                      Debug mode
     -h                      Show this message
 EOF
-    [ -n "$ERROR" ] && exit 1 || exit 0
+    [[ -n "$ERROR" ]] && exit 1 || exit 0
 }
 
-while getopts "hu:b:B:V:m:r:U:p:D:C:w:c:e:E:d" OPTION
+while getopts "hu:b:B:V:m:r:U:p:D:C:w:c:e:E:d" OPTION; do
-do
     case $OPTION in
         u)
             PG_USER=$OPTARG
@@ -117,12 +116,12 @@ do
             REPLAY_CRITICAL_DELAY=$OPTARG
         ;;
         e)
-            [ "$OPTARG" != "sync" -a "$OPTARG" != "async" ] && \
+            [[ "$OPTARG" != "sync" ]] && [[ "$OPTARG" != "async" ]] && \
                 usage "Invalid expected replication state '$OPTARG'. Possible values: sync or async."
             EXPECTED_SYNC_STATE=$OPTARG
         ;;
         E)
-            [ "$OPTARG" != "master" -a "$OPTARG" != "hot-standby" -a "$OPTARG" != "auto" ] && \
+            [[ "$OPTARG" != "master" ]] && [[ "$OPTARG" != "hot-standby" ]] && [[ "$OPTARG" != "auto" ]] && \
                 usage "Invalid expected mode '$OPTARG'. Possible values: master, hot-standby or auto."
             EXPECTED_MODE=$OPTARG
         ;;
@@ -139,8 +138,7 @@ do
 done
 
 function debug() {
-    if [ $DEBUG -eq 1 ]
+    if [[ $DEBUG -eq 1 ]]; then
-    then
         >&2 echo -e "[DEBUG] $1"
     fi
 }
@@ -163,64 +161,62 @@ EXPECTED_MODE = $EXPECTED_MODE
 "
 
 # Auto-detect PostgreSQL information using pg_lsclusters
-if [ -x "$PG_LSCLUSTER_BIN" ]
+if [[ -x "$PG_LSCLUSTER_BIN" ]]; then
-then
     PG_CLUSTER=$( $PG_LSCLUSTER_BIN -h 2>/dev/null|head -n1 )
-    if [ -n "$PG_CLUSTER" ]
+    if [[ -n "$PG_CLUSTER" ]]; then
-    then
         debug "pg_lsclusters output:\n\t$PG_CLUSTER"
         # Output example:
         # 9.6 main    5432 online,recovery postgres /var/lib/postgresql/9.6/main /var/log/postgresql/postgresql-9.6-main.log
-        [ -z "$PG_VERSION" ] && PG_VERSION=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $1}' )
+        [[ -z "$PG_VERSION" ]] && PG_VERSION=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $1}' )
-        [ -z "$PG_DEFAULT_PORT" ] && PG_DEFAULT_PORT=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $3}' )
+        [[ -z "$PG_DEFAULT_PORT" ]] && PG_DEFAULT_PORT=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $3}' )
-        [ -z "$PG_USER" ] && PG_USER=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $5}' )
+        [[ -z "$PG_USER" ]] && PG_USER=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $5}' )
-        [ -z "$PG_MAIN" ] && PG_MAIN=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $6}' )
+        [[ -z "$PG_MAIN" ]] && PG_MAIN=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $6}' )
     fi
 else
     debug "pg_lsclusters not found ($PG_LSCLUSTER_BIN): parameters auto-detection disabled"
 fi
 
 # If auto-detection failed, use default values
-[ -z "$PG_USER" ] && PG_USER="$DEFAULT_PG_USER"
+[[ -z "$PG_USER" ]] && PG_USER="$DEFAULT_PG_USER"
-[ -z "$PG_VERSION" ] && PG_VERSION="$DEFAULT_PG_VERSION"
+[[ -z "$PG_VERSION" ]] && PG_VERSION="$DEFAULT_PG_VERSION"
-[ -z "$PG_MAIN" ] && PG_MAIN="$DEFAULT_PG_MAIN"
+[[ -z "$PG_MAIN" ]] && PG_MAIN="$DEFAULT_PG_MAIN"
-[ -z "$PG_DEFAULT_PORT" ] && PG_DEFAULT_PORT="$DEFAULT_PG_PORT"
+[[ -z "$PG_DEFAULT_PORT" ]] && PG_DEFAULT_PORT="$DEFAULT_PG_PORT"
 
 # Check PG_USER
-[ -z "$PG_USER" ] && echo "UNKNOWN: Postgres user not specified" && exit 3
+[[ -z "$PG_USER" ]] && echo "UNKNOWN: Postgres user not specified" && exit 3
-id "$PG_USER" > /dev/null 2>&1
+id "$PG_USER" > /dev/null 2>&1 || { echo "UNKNOWN: Invalid Postgres user ($PG_USER)"; exit 3; }
-[ $? -ne 0 ] && echo "UNKNOWN: Invalid Postgres user ($PG_USER)" && exit 3
 
 # Check PSQL_BIN
-[ ! -x "$PSQL_BIN" ] && echo "UNKNOWN: Invalid psql bin path ($PSQL_BIN)" && exit 3
+[[ ! -x "$PSQL_BIN" ]] && echo "UNKNOWN: Invalid psql bin path ($PSQL_BIN)" && exit 3
 
 # Check PG_MAIN
-[ ! -d "$PG_MAIN/" ] && echo "UNKNOWN: Invalid Postgres main directory path ($PG_MAIN)" && exit 3
+[[ ! -d "$PG_MAIN/" ]] && echo "UNKNOWN: Invalid Postgres main directory path ($PG_MAIN)" && exit 3
 
 # Check RECOVERY_CONF
-if [ -z "$RECOVERY_CONF" ]; then
+if [[ -z "$RECOVERY_CONF" ]]; then
-    [ $PG_VERSION -le 11 ] && RECOVERY_CONF_FILENAME="recovery.conf" || RECOVERY_CONF_FILENAME="postgresql.auto.conf"
+    [[ $PG_VERSION -le 11 ]] && RECOVERY_CONF_FILENAME="recovery.conf" || RECOVERY_CONF_FILENAME="postgresql.auto.conf"
     RECOVERY_CONF="$PG_MAIN/$RECOVERY_CONF_FILENAME"
 else
     RECOVERY_CONF_FILENAME=$( basename "$RECOVERY_CONF" )
 fi
 
 # Check PG_DEFAULT_PORT
-[ $( echo "$PG_DEFAULT_PORT"|grep -c -E '^[0-9]*$' ) -ne 1 ] && "UNKNOWN: Postgres default master TCP port must be an integer." && exit 3
+[[ $( grep -c -E '^[0-9]*$' <<< "$PG_DEFAULT_PORT" ) -ne 1 ]] && \
+  echo "UNKNOWN: Postgres default master TCP port must be an integer." && exit 3
 
 # If PG_DB is not provided with -D parameter, use PG_USER as default value
-[ -z "$PG_DB" ] && PG_DB="$PG_USER"
+[[ -z "$PG_DB" ]] && PG_DB="$PG_USER"
 
 function psql_get () {
     sql="$1"
     debug "Exec 'echo \"$sql\"|sudo -u $PG_USER $PSQL_BIN -d \"$PG_DB\" -w -t -P format=unaligned"
-    echo "$sql"|sudo -u $PG_USER $PSQL_BIN -d "$PG_DB" -w -t -P format=unaligned
+    sudo -u "$PG_USER" "$PSQL_BIN" -d "$PG_DB" -w -t -P format=unaligned <<< "$sql"
 }
 
 function psql_master_get () {
     sql="$1"
     debug "Exec 'echo \"$sql\"|sudo -u $PG_USER $PSQL_BIN -U $M_USER -h $M_HOST -w -p $M_PORT -d $PG_DB -t -P format=unaligned"
-    echo "$sql"|sudo -u $PG_USER $PSQL_BIN -U $M_USER -h $M_HOST -w -p $M_PORT -d $PG_DB -t -P format=unaligned
+    sudo -u "$PG_USER" "$PSQL_BIN" -U "$M_USER" -h "$M_HOST" -w -p "$M_PORT" -d "$PG_DB" -t -P format=unaligned <<< "$sql"
 }
 
 debug "Running options:
@@ -239,8 +235,7 @@ REPLAY_CRITICAL_DELAY = $REPLAY_CRITICAL_DELAY
 "
 
 # Set some stuff to PostgreSQL version
-if [ $( echo "$PG_VERSION < 10" |bc -l ) -eq 1 ]
+if [[ $( bc -l <<< "$PG_VERSION < 10" ) -eq 1 ]]; then
-then
     pg_last_wal_receive_lsn='pg_last_xlog_receive_location()'
     pg_last_wal_replay_lsn='pg_last_xlog_replay_location()'
     pg_current_wal_lsn='pg_current_xlog_location()'
@@ -257,28 +252,28 @@ else
 fi
 
 # Postgres is running ?
-if [ $DEBUG -eq 0 ]
+if [[ $DEBUG -eq 0 ]]; then
-then
     psql_get '\q' 2> /dev/null
+    is_running=$?
 else
     psql_get '\q'
+    is_running=$?
 fi
-if [ $? -ne 0 ]
+if [[ $is_running -ne 0 ]]; then
-then
     echo "CRITICAL: Postgres is not running !"
     exit 2
 fi
 debug "Postgres is running"
 
 RECOVERY_MODE=0
-[ "$( psql_get 'SELECT pg_is_in_recovery();' )" == "t" ] && RECOVERY_MODE=1
+[[ "$( psql_get 'SELECT pg_is_in_recovery();' )" == "t" ]] && RECOVERY_MODE=1
 
-if [ "$EXPECTED_MODE" == "auto" ]; then
+if [[ "$EXPECTED_MODE" == "auto" ]]; then
     debug "Auto-detect mode"
     if [[ $RECOVERY_MODE -eq 1 ]]; then
         debug "Postgres is in recovery mode. Hot-standby mode."
         EXPECTED_MODE="hot-standby"
-    elif [ -f $RECOVERY_CONF -a $( grep -cE '^\s*primary_conninfo' $RECOVERY_CONF ) -gt 0 ]; then
+    elif [[ -f $RECOVERY_CONF ]] && [[ $( grep -cE '^\s*primary_conninfo' "$RECOVERY_CONF" ) -gt 0 ]]; then
         debug "File $RECOVERY_CONF_FILENAME found and contain primary_conninfo. Hot-standby mode."
         EXPECTED_MODE="hot-standby"
     else
@@ -288,11 +283,9 @@ if [ "$EXPECTED_MODE" == "auto" ]; then
     fi
 fi
 
-if [ "$EXPECTED_MODE" == "hot-standby" ]
+if [[ "$EXPECTED_MODE" == "hot-standby" ]]; then
-then
     # Check recovery mode
-    if [ $RECOVERY_MODE -ne 1 ]
+    if [[ $RECOVERY_MODE -ne 1 ]]; then
-    then
         echo "CRITICAL: Not in recovery mode while $RECOVERY_CONF_FILENAME file found !"
         exit 2
     fi
@@ -307,38 +300,33 @@ then
 
     # Get master connection information from primary_conninfo configuration parameter
     MASTER_CONN_INFOS=$( psql_get "SHOW primary_conninfo" )
-    if [ ! -n "$MASTER_CONN_INFOS" ]
+    if [[ -z "$MASTER_CONN_INFOS" ]]; then
-    then
         echo "UNKNOWN: Can't retrieve master connection information from primary_conninfo configuration parameter"
         exit 3
     fi
     debug "Master connection information: $MASTER_CONN_INFOS"
 
-    M_HOST=$( echo "$MASTER_CONN_INFOS"| grep 'host=' | sed 's/^.*host= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
+    M_HOST=$( grep 'host=' <<< "$MASTER_CONN_INFOS" | sed 's/^.*host= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
-    if [ ! -n "$M_HOST" ]
+    if [[ -z "$M_HOST" ]]; then
-    then
         echo "UNKNOWN: Can't retrieve master host from primary_conninfo configuration parameter"
         exit 3
     fi
     debug "Master host: $M_HOST"
 
-    M_PORT=$( echo "$MASTER_CONN_INFOS"| grep 'port=' | sed 's/^.*port= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
+    M_PORT=$( grep 'port=' <<< "$MASTER_CONN_INFOS" | sed 's/^.*port= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
-    if [ ! -n "$M_PORT" ]
+    if [[ -z "$M_PORT" ]]; then
-    then
         debug "Master port not specified, use default: $PG_DEFAULT_PORT"
         M_PORT=$PG_DEFAULT_PORT
     else
         debug "Master port: $M_PORT"
     fi
 
-    if [ -n "$PG_MASTER_USER" ]
+    if [[ -n "$PG_MASTER_USER" ]]; then
-    then
         debug "Master user provided by command-line, use it: $PG_MASTER_USER"
         M_USER="$PG_MASTER_USER"
     else
-        M_USER=$( echo "$MASTER_CONN_INFOS"| grep 'user=' | sed 's/^.*user= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
+        M_USER=$( grep 'user=' <<< "$MASTER_CONN_INFOS" | sed 's/^.*user= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
-        if [ ! -n "$M_USER" ]
+        if [[ -z "$M_USER" ]]; then
-        then
             debug "Master user not specified, use default: $PG_USER"
             M_USER=$PG_USER
         else
@@ -346,16 +334,13 @@ then
         fi
     fi
 
-    M_APP_NAME=$( echo "$MASTER_CONN_INFOS"| grep 'application_name=' | sed "s/^.*application_name=[ \'\"]*\([^ \'\"]\+\)[ \'\"]*.*$/\1/" )
+    M_APP_NAME=$( grep 'application_name=' <<< "$MASTER_CONN_INFOS" | sed "s/^.*application_name=[ \'\"]*\([^ \'\"]\+\)[ \'\"]*.*$/\1/" )
-    if [ ! -n "$M_APP_NAME" ]
+    if [[ -z "$M_APP_NAME" ]]; then
-    then
+        if [[ $PG_VERSION -ge 12 ]]; then
-        if [ $PG_VERSION -ge 12 ]
-        then
             debug "Master application name not specified, use cluster_name if defined"
             CLUSTER_NAME=$( psql_get "SELECT current_setting('cluster_name')" )
             debug "Cluster name: $CLUSTER_NAME"
-            if [ -n "$CLUSTER_NAME" ]
+            if [[ -n "$CLUSTER_NAME" ]]; then
-            then
                 M_APP_NAME=$CLUSTER_NAME
             else
                 debug "Cluster name not defined, use default: $PG_DEFAULT_APP_NAME"
@@ -371,48 +356,42 @@ then
 
     # Get current replication state information from master
     M_CUR_REPL_STATE_INFO="$( psql_master_get "SELECT state, sync_state, $sent_lsn AS sent_lsn, $write_lsn AS write_lsn FROM pg_stat_replication WHERE application_name='$M_APP_NAME';" )"
-    if [ ! -n "$M_CUR_REPL_STATE_INFO" ]
+    if [[ -z "$M_CUR_REPL_STATE_INFO" ]]; then
-    then
         echo "UNKNOWN: Can't retrieve current replication state information from master server"
         exit 3
     fi
     debug "Master current replication state:\n\tstate|sync_state|sent_lsn|write_lsn\n\t$M_CUR_REPL_STATE_INFO"
 
-    M_CUR_STATE=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f1 )
+    M_CUR_STATE=$( cut -d'|' -f1 <<< "$M_CUR_REPL_STATE_INFO" )
     debug "Master current state: $M_CUR_STATE"
-    if [ "$M_CUR_STATE" != "streaming" ]
+    if [[ "$M_CUR_STATE" != "streaming" ]]; then
-    then
         echo "CRITICAL: this host is not in streaming state according to master host (current state = '$M_CUR_STATE')"
         exit 2
     fi
 
-    M_CUR_SYNC_STATE=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f2 )
+    M_CUR_SYNC_STATE=$( cut -d'|' -f2 <<< "$M_CUR_REPL_STATE_INFO" )
     debug "Master current sync state: $M_CUR_SYNC_STATE"
-    if [ "$M_CUR_SYNC_STATE" != "$EXPECTED_SYNC_STATE" ]
+    if [[ "$M_CUR_SYNC_STATE" != "$EXPECTED_SYNC_STATE" ]]; then
-    then
         echo "CRITICAL: unexpected replication state '$M_CUR_SYNC_STATE' (expected state = '$EXPECTED_SYNC_STATE')"
         exit 2
     fi
 
-    M_CUR_SENT_LSN=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f3 )
+    M_CUR_SENT_LSN=$( cut -d'|' -f3 <<< "$M_CUR_REPL_STATE_INFO" )
-    M_CUR_WRITED_LSN=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f4 )
+    M_CUR_WRITED_LSN=$( cut -d'|' -f4 <<< "$M_CUR_REPL_STATE_INFO" )
     debug "Master current last sent/writed LSN: '$M_CUR_SENT_LSN' / '$M_CUR_WRITED_LSN'"
 
     # Check current master LSN vs last received LSN
-    if [ "$CHECK_CUR_MASTER_LSN" == "1" ]
+    if [[ "$CHECK_CUR_MASTER_LSN" == "1" ]]; then
-    then
         # Get current LSN from master
         M_CUR_LSN="$( psql_master_get "SELECT $pg_current_wal_lsn" )"
-        if [ ! -n "$M_CUR_LSN" ]
+        if [[ -z "$M_CUR_LSN" ]]; then
-        then
             echo "UNKNOWN: Can't retrieve current LSN from master server"
             exit 3
         fi
         debug "Master current LSN: $M_CUR_LSN"
 
         # Master current LSN is the last received LSN ?
-        if [ "$M_CUR_LSN" != "$LAST_RECEIVED_LSN" ]
+        if [[ "$M_CUR_LSN" != "$LAST_RECEIVED_LSN" ]]; then
-        then
             echo "CRITICAL: Master current LSN is not the last received LSN"
             exit 2
         fi
@@ -420,18 +399,15 @@ then
     fi
 
     # The last received LSN is the last replayed ?
-    if [ "$LAST_RECEIVED_LSN" != "$LAST_REPLAYED_LSN" ]
+    if [[ "$LAST_RECEIVED_LSN" != "$LAST_REPLAYED_LSN" ]]; then
-    then
         debug "/!\ The last received LSN is NOT the last replayed LSN ('$M_CUR_LSN' / '$LAST_REPLAYED_LSN')"
         REPLAY_DELAY="$( psql_get 'SELECT EXTRACT(EPOCH FROM now() - pg_last_xact_replay_timestamp());' )"
         debug "Replay delay is $REPLAY_DELAY second(s)"
-        if [ $( echo "$REPLAY_DELAY >= $REPLAY_CRITICAL_DELAY"|bc -l ) -gt 0 ]
+        if [[ $( bc -l <<< "$REPLAY_DELAY >= $REPLAY_CRITICAL_DELAY" ) -gt 0 ]]; then
-        then
             echo "CRITICAL: last received LSN is not the last replayed ('$LAST_RECEIVED_LSN' / '$LAST_REPLAYED_LSN') and replay delay is $REPLAY_DELAY second(s)"
             exit 2
         fi
-        if [ $( echo "$REPLAY_DELAY >= $REPLAY_WARNING_DELAY"|bc -l ) -gt 0 ]
+        if [[ $( bc -l <<< "$REPLAY_DELAY >= $REPLAY_WARNING_DELAY" ) -gt 0 ]]; then
-        then
             echo "WARNING: last received LSN is not the last replay file ('$LAST_RECEIVED_LSN' / '$LAST_REPLAYED_LSN') and replay delay is $REPLAY_DELAY second(s)"
             exit 1
         fi
@@ -440,8 +416,7 @@ then
     debug "Last received LSN is the last replayed file"
 
     # The master last sent LSN is the last received (and synced) ?
-    if [ "$M_CUR_SENT_LSN" != "$LAST_RECEIVED_LSN" ]
+    if [[ "$M_CUR_SENT_LSN" != "$LAST_RECEIVED_LSN" ]]; then
-    then
         echo "WARNING: master last sent LSN is not already received (and synced to disk) by slave. May be we have some network delay or load on slave"
         echo "Master last sent LSN: $M_CUR_SENT_LSN"
         echo "Slave last received (and synced to disk) LSN: $LAST_RECEIVED_LSN"
@@ -451,13 +426,11 @@ then
     echo "OK: Hot-standby server is up-to-date"
     echo "Replication state: $M_CUR_SYNC_STATE"
     echo "Last sent/writed LSN: '$M_CUR_SENT_LSN' / '$M_CUR_WRITED_LSN'"
-    [ "$LAST_RECEIVED_LSN" != "$LAST_REPLAYED_LSN" ] && echo "Replay delay: ${REPLAY_DELAY}s"
+    [[ "$LAST_RECEIVED_LSN" != "$LAST_REPLAYED_LSN" ]] && echo "Replay delay: ${REPLAY_DELAY}s"
     exit 0
-elif [ "$EXPECTED_MODE" == "master" ]
+elif [[ "$EXPECTED_MODE" == "master" ]]; then
-then
     # Check recovery mode
-    if [ $RECOVERY_MODE -eq 1 ]
+    if [[ $RECOVERY_MODE -eq 1 ]]; then
-    then
         echo "CRITICAL: In recovery mode while expected mode is master!"
         exit 2
     fi
@@ -465,8 +438,7 @@ then
 
     # Retrieve current lsn
     CURRENT_LSN=$( psql_get "SELECT $pg_current_wal_lsn" )
-    if [ -z "$CURRENT_LSN" ]
+    if [[ -z "$CURRENT_LSN" ]]; then
-    then
         echo "UNKNOWN: Fail to retrieve current LSN (Log Sequence Number)"
         exit 3
     fi
@@ -482,33 +454,30 @@ then
         FROM pg_stat_replication
       ) AS s2
     ) AS s1" )
-    if [ ! -n "$STANDBY_CLIENTS" ]
+    if [[ -z "$STANDBY_CLIENTS" ]]; then
-    then
         echo "WARNING: no stand-by client connected"
         exit 1
     fi
-    debug "Stand-by client(s):\n\t$( echo -e "$STANDBY_CLIENTS"|sed 's/\n/\n\t/' )"
+    debug "Stand-by client(s):\n\t${STANDBY_CLIENTS//$'\n'/\\n\\t}"
 
     STANDBY_CLIENTS_TXT=""
     STANDBY_CLIENTS_COUNT=0
     CURRENT_LSN_IS_LAST_SENT=1
-    for line in $STANDBY_CLIENTS
+    for line in $STANDBY_CLIENTS; do
-    do
+        (( STANDBY_CLIENTS_COUNT+=1 ))
-        let STANDBY_CLIENTS_COUNT=STANDBY_CLIENTS_COUNT+1
 
-        NAME=$( echo $line|cut -d '|' -f 1 )
+        NAME=$( cut -d '|' -f 1 <<< "$line" )
-        IP=$( echo $line|cut -d '|' -f 2 )
+        IP=$( cut -d '|' -f 2 <<< "$line" )
-        SENT_LSN=$( echo $line|cut -d '|' -f 3 )
+        SENT_LSN=$( cut -d '|' -f 3 <<< "$line" )
-        WRITED_LSN=$( echo $line|cut -d '|' -f 4 )
+        WRITED_LSN=$( cut -d '|' -f 4 <<< "$line" )
-        STATE=$( echo $line|cut -d '|' -f 5 )
+        STATE=$( cut -d '|' -f 5 <<< "$line" )
-        SYNC_STATE=$( echo $line|cut -d '|' -f 6 )
+        SYNC_STATE=$( cut -d '|' -f 6 <<< "$line" )
-        LAG=$( echo $line|cut -d '|' -f 7 )
+        LAG=$( cut -d '|' -f 7 <<< "$line" )
         STANDBY_CLIENTS_TXT="$STANDBY_CLIENTS_TXT\n$NAME ($IP): $STATE/$SYNC_STATE (LSN: sent='$SENT_LSN' / writed='$WRITED_LSN', Lag: ${LAG}b)"
-        [ "$SENT_LSN" != "$CURRENT_LSN" ] && CURRENT_LSN_IS_LAST_SENT=0
+        [[ "$SENT_LSN" != "$CURRENT_LSN" ]] && CURRENT_LSN_IS_LAST_SENT=0
     done
 
-    if [ $CURRENT_LSN_IS_LAST_SENT -eq 1 ]
+    if [[ $CURRENT_LSN_IS_LAST_SENT -eq 1 ]]; then
-    then
         echo "OK: $STANDBY_CLIENTS_COUNT stand-by client(s) connected"
         EXIT_CODE=0
     else