As per the en.wikibooks.org:

Bash is a “Unix shell”: a command-line interface for interacting with the operating system. It has the ability to run an entire script of commands, known as a “Bash shell script”.

I recently started to create UNIX / LINUX Bash Shell script for enhancing my PostgreSQL DBA Work. You can create a Bash shell script and can connect PostgreSQL using psql.

In this post, I am sharing a sample bash shell script to execute psql commands.

Open a new file in vi editor:

[root@dbrnd anvesh]$ vi helloworld.bash

Press [i] key to get an insert prompt:

Copy below sample Bash Shell Script and Paste into vi editor:

#!/bin/bash

###################################################
# First Bash Shell script to execute psql command 
###################################################

#Set the value of variable
database="database_name"

#Execute few psql commands: 
#Note: you can also add -h hostname -U username in the below commands. 

psql -d $database -c "CREATE TABLE public.tbl_students(rno integer, name character varying)"
psql -d $database -c "INSERT INTO public.tbl_students VALUES (1,'Anvesh'),(2,'Neevan'),(3,'Roy'),(4,'Martin'),(5,'Jenny')"
psql -d $database -c "SELECT *FROM public.tbl_students"

#Assign table count to variable
TableCount=$(psql -d $database -t -c "select count(1) from public.tbl_students")

#Print the value of variable
echo "Total table records count....:"$TableCount

Press [Esc] key to get a command prompt and execute below command:
To save and exit vi editor.

:wq

Give permission to the file:

[root@dbrnd anvesh]$ chmod +x helloworld.bash

Execute this file:

[root@dbrnd anvesh]$ ./helloworld.bash

You can find below result:

rno |  name
-----+--------
   1 | Anvesh
   5 | Jenny
   2 | Neevan
   3 | Roy
   4 | Martin
(5 rows)

Total table records count....: 5