Export data from PostgreSQL to JSON via command line on MacOS

Want to export PostgreSQL data to JSON Lines (JSONL) file via Command Line Interface (CLI) on MacOS?

Using pg-cmd, Command Line Interface (CLI) client for PostgreSQL, you can unload PostgreSQL data to JSON easily and fast. Direct Interaction or Scripting and Automation.

• No need to install PostgreSQL client library.
• Convenient to deploy to cloud. No need to run installation file, just uncompress and run, immediately.
• Commands are entered into a terminal or command prompt, accessed from local or remote (like SSH).
• Support Windows, Linux, and MacOS.

Download pg-cmd Macos version
pg-cmd.darwin-amd64.zip
pg-cmd.darwin-arm64.zip

JSON Lines text format, also called newline-delimited JSON (NDJSON), or Line-delimited JSON (LDJSON). JSON Lines files may be saved with the file extension .jsonl, *.ndjson, *.ldjson.

Export PostgreSQL data to JSON via command line on MacOS

1. Unload Table.

1) In interactive mode:

pg-cmd> unload table=jobs datafile=e:\temp\tables\jobs.json filetype=json;

2) In batch mode:

pg-cmd dsn="pan:withdata@192.168.0.102/test" task=unload table=jobs datafile=e:\temp\tables\jobs.json filetype=json quit=y

2. Unload Query.

1) In interactive mode:

pg-cmd> unload query="select job_id,job_title from jobs"
     >  datafile=e:\temp\tables\jobs_part.json
     >  filetype=json;

2) In batch mode:

pg-cmd dsn="pan:withdata@192.168.0.102/test" task=unload query="select job_id,job_title from jobs" datafile=e:\temp\tables\jobs_part.json filetype=json quit=y

3. Unload All Tables.

1) In interactive mode:

pg-cmd> unload table=all folder=e:\temp\tables filetype=json;

2) In batch mode:

pg-cmd dsn="pan:withdata@192.168.0.102/test" task=unload table=all folder=e:\temp\tables filetype=json quit=y

See parameters detail.

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More about pg-cmd – Command Line Interface (CLI) tool for PostgreSQL

PostgreSQL → JSON reference

Type mapping

Value kind	in PostgreSQL	in JSON
Int	integer	1234 (number)
Bigint	bigint	9007199254740993
Decimal	numeric(p,s)	1234.56 (number)
Float	double precision	1.234e10 (number)
Text	varchar(n)	"text" (string)
Long text	text	"multi-line\ntext" (escaped newline inside a string)
Date	date	"2026-09-18" (string)
Datetime	timestamp	"2026-09-18T14:30:00Z" (string)
Binary	bytea	"base64:..." (string)
Boolean	boolean	true / false (boolean)
JSON	jsonb	nested object or array, kept as structure

Dialect differences

PostgreSQL is a database server and JSON is a file format, so the gap is wider than a dialect difference - the rows below are where values and structure stop lining up.

Property	in PostgreSQL	in JSON
port	5432	—
identifiers	"double quotes"	Double quotes; backslash escapes
row limit	LIMIT n	—
dates	timestamp, timestamptz, date, time	No date type: dates arrive as strings and the reader must p...
long text	TEXT	—
binary	BYTEA	Not supported natively - base64 inside a string
separator	—	Braces and commas
encoding	—	UTF-8 by definition
typing	—	string, number, boolean, null, object, array - no date type
shape	Tables of rows and columns	Nested objects and arrays
ceiling	—	Whole document is usually parsed into memory

Command line

Side	Command
PostgreSQL	pg_dump or COPY ... TO
PostgreSQL (load)	COPY ... FROM

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