diff --git a/packages/clickhouse-keeper.postinstall b/packages/clickhouse-keeper.postinstall
index 3d6cd484146..2b4f303b684 100644
--- a/packages/clickhouse-keeper.postinstall
+++ b/packages/clickhouse-keeper.postinstall
@@ -3,12 +3,12 @@ set -e
 # set -x
 
 PROGRAM=clickhouse-keeper
-KEEPER_USER=${KEEPER_USER:=clickhouse}
-KEEPER_GROUP=${KEEPER_GROUP:=clickhouse}
+KEEPER_USER=${KEEPER_USER:-clickhouse}
+KEEPER_GROUP=${KEEPER_GROUP:-clickhouse}
 # Please note that we don't support paths with whitespaces. This is rather ignorant.
-KEEPER_CONFDIR=${KEEPER_CONFDIR:=/etc/$PROGRAM}
-KEEPER_DATADIR=${KEEPER_DATADIR:=/var/lib/clickhouse}
-KEEPER_LOGDIR=${KEEPER_LOGDIR:=/var/log/$PROGRAM}
+KEEPER_CONFDIR=${KEEPER_CONFDIR:-/etc/$PROGRAM}
+KEEPER_DATADIR=${KEEPER_DATADIR:-/var/lib/clickhouse}
+KEEPER_LOGDIR=${KEEPER_LOGDIR:-/var/log/$PROGRAM}
 
 [ -f /usr/share/debconf/confmodule ] && . /usr/share/debconf/confmodule
 [ -f /etc/default/clickhouse-keeper ] && . /etc/default/clickhouse-keeper
diff --git a/packages/clickhouse-server.postinstall b/packages/clickhouse-server.postinstall
index 2b9830faf3b..f5d473f7c9b 100644
--- a/packages/clickhouse-server.postinstall
+++ b/packages/clickhouse-server.postinstall
@@ -3,14 +3,14 @@ set -e
 # set -x
 
 PROGRAM=clickhouse-server
-CLICKHOUSE_USER=${CLICKHOUSE_USER:=clickhouse}
-CLICKHOUSE_GROUP=${CLICKHOUSE_GROUP:=${CLICKHOUSE_USER}}
+CLICKHOUSE_USER=${CLICKHOUSE_USER:-clickhouse}
+CLICKHOUSE_GROUP=${CLICKHOUSE_GROUP:-${CLICKHOUSE_USER}}
 # Please note that we don't support paths with whitespaces. This is rather ignorant.
-CLICKHOUSE_CONFDIR=${CLICKHOUSE_CONFDIR:=/etc/clickhouse-server}
-CLICKHOUSE_DATADIR=${CLICKHOUSE_DATADIR:=/var/lib/clickhouse}
-CLICKHOUSE_LOGDIR=${CLICKHOUSE_LOGDIR:=/var/log/clickhouse-server}
-CLICKHOUSE_BINDIR=${CLICKHOUSE_BINDIR:=/usr/bin}
-CLICKHOUSE_GENERIC_PROGRAM=${CLICKHOUSE_GENERIC_PROGRAM:=clickhouse}
+CLICKHOUSE_CONFDIR=${CLICKHOUSE_CONFDIR:-/etc/clickhouse-server}
+CLICKHOUSE_DATADIR=${CLICKHOUSE_DATADIR:-/var/lib/clickhouse}
+CLICKHOUSE_LOGDIR=${CLICKHOUSE_LOGDIR:-/var/log/clickhouse-server}
+CLICKHOUSE_BINDIR=${CLICKHOUSE_BINDIR:-/usr/bin}
+CLICKHOUSE_GENERIC_PROGRAM=${CLICKHOUSE_GENERIC_PROGRAM:-clickhouse}
 CLICKHOUSE_PIDDIR=/var/run/$PROGRAM
 
 [ -f /usr/share/debconf/confmodule ] && . /usr/share/debconf/confmodule