How to parse the correct version number?

Question

The command below will return the corresponding strings

$ docker-compose exec postgres postgres --version
postgres (PostgreSQL) 10.4 (Debian 10.4-2.pgdg90+1)

I am trying to get the postgresql version but when I tried, the Debian version and other numbers are included like

$ pg_version=$(docker-compose exec postgres postgres --version | sed 's/[^0-9.]//g')
10.410.42.901

I am wondering how to get the 10.4 only

You could hack it at spaces etc. ... but I'd use one of the other methods (like SHOW server_version): https://stackoverflow.com/questions/13733719/which-version-of-postgresql-am-i-running — James Antill, Jul 30 '18 at 02:30

score 2 · Answer 1 · answered Jul 30 '18 at 12:11

2

awk -v RS=" " '/^[0-9.]+$/{print; exit}'
grep -oE '[.0-9]+' | head -1
tr ' ' '\n' | grep -oE -m 1 '[.0-9]+'
sed 's|^[^0-9.]*$[0-9.]\+$.*|\1|'

answered Jul 30 '18 at 12:11

kvantour

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CWLiu · Accepted Answer · 2018-07-30T02:56:49.553

1

Modify the sed as followed would help,

sed -E 's/.*PostgreSQL[^0-9.]+([0-9.]*).*/\1/'

\1 would only match to the version number right behind "PostgreSQL".

edited Jul 30 '18 at 02:56

answered Jul 30 '18 at 02:33

CWLiu

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Sumit · Answer 3 · 2018-07-30T11:27:17.860

1

pg_version=$(docker-compose exec postgres postgres -V | grep -oE '[.0-9]+' | head -1)

edited Jul 30 '18 at 11:27

answered Jul 30 '18 at 02:53

Sumit

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`10.4 10.4`. This value returned. How to return only one 10.4? – Dean Christian Armada Jul 30 '18 at 02:59
Since it finds the version two times, put `head -1` to print first one. – Sumit Jul 30 '18 at 03:35
@Sumit : I think the egrep pattern `[.0-9]+` would be sufficient in this case. BTW, it's better to write it as `grep -oE`, since `egrep` is deprecated. – user1934428 Jul 30 '18 at 10:03
@user1934428 Yeah, Thanks – Sumit Jul 30 '18 at 11:27

score 0 · Answer 4 · answered Jul 30 '18 at 11:41

You could use grep with something like this:

$ grep -oP "PostgreSQL.\s\K.+?(?=\s)"

For example:

$ echo "postgres (PostgreSQL) 10.4 (Debian 10.4-2.pgdg90+1)" | grep -oP "SQL.\s\K.+?(?=\s)"
10.4

The \K can be read as excluding everything to the left *SQL)<space> before it and return only the right part .+?(?=\s) until and space \s is found.

How to parse the correct version number?

4 Answers4