first of all you need to install it:  apt install postgresql   then specify data dir for it by typing:  initd -D YOUR_DATA_DIR   example YOUR_DATA_DIR is /data/data/com.termux/files/home/mydb   note that you don't need to make the dir first, you just need the dir name then initdb will create it automatically :)   in this example like this:  initdb -D /data/data/com.termux/files/home/mydb   The files belonging to this database system will be owned by user "u0_a171".  This user must also own the server process.   The database cluster will be initialized with locale "C.UTF-8".  The default text search configuration will be set to "english".   Data page checksums are disabled.   creating directory test ... ok  creating subdirectories ... ok  selecting dynamic shared memory implementation ... sysv  selecting default max_connections ... 100  selecting default shared_buffers ... 128MB  selecting default time zone ... Asia/Jakarta  creating configuration files...