How can I check if PostgreSQL is installed or not via Linux script

Question

I want to check in a script if PostgreSQL is installed or not on Linux and print the result   Any suggestions on how to do the check

User · Answer

aptitude show postgresql   grep Version worked for me

User · Answer

And if everything else fails from these great choice of answers  you can always use  find  like this  Or you may need to use sudo   If you are root  just type    gt  find   -name  postgres   If you are a user  you will need sudo priv s to run it through all the directories   I run it this way  from the   base to find the whole path that the element is found in  This will return any files or directories with the  postgres  in it   You could do the same thing looking for the pg hba conf or postgresql conf files also

User · Answer

For many years I used the command    ps aux   grep postgres   On one hand it is useful  for any process  and gives useful info  but from process POV   But on the other hand it is for checking if the server you know  you already installed is running   At some point I found this tutorial  where the usage of the locate command is shown  It looks like this command is much more to the point for this case

User · Answer

We can simply write   psql --version   output show like   psql  PostgreSQL  11 5  Ubuntu 11 5-1 pgdg18 04 1

User · Answer

There is no straightforward way to do this   All you can do is check with the package manager  rpm  dpkg  or probe some likely locations for the files you want   Or you could try to connect to a likely port  5432  and see if you get a PostgreSQL protocol response   But none of this is going to be very robust   You might want to review your requirements

User · Answer

There is no single simple way to do it  because PostgreSQL might be installed and set up in many different ways    Installed from source in a user home directory Installed from source into  opt or  usr local  manually started or started by an init script Installed from distributor rpm   deb packages and started via init script Installed from 3rd party rpm   deb packages and started via init script Installed from packages but not set to start Client installed  connecting to a server on a different computer Installed and running but not on the default PATH or default port   You can t rely on psql being on the PATH  You can t rely on there being only one psql on the system  multiple versions might be installed in different ways   You can t do it based on port  as there s no guarantee it s on port 5432  or that there aren t multiple versions   Prompt the user and ask them

User · Answer

What about trying the which command   If you were to run which psql and Postgres is not installed there appears to be no output  You just get the terminal prompt ready to accept another command    gt  which psql  gt    But if Postgres is installed you ll get a response with the path to the location of the Postgres install    gt  which psql  opt boxen homebrew bin psql   Looking at man which there also appears to be an option that could help you out   -s      No output  just return 0 if any of the executables are found  or         1 if none are found    So it seems like as long as whatever scripting language you re using can can execute a terminal command you could send which -s psql and use the return value to determine if Postgres is installed  From there you can print that result however you like   I do have postgres installed on my machine so I run the following   gt  which -s psql  gt  echo    0   which tells me that the command returned 0  indicating that the Postgres executable was found on my machine   Here s the information about using echo

User · Answer

Go to bin directory of postgres db such as  opt postgresql bin  amp  run below command           bin     psql --version  psql  PostgreSQL  9 0 4   Here you go

User · Answer

If it is debian based   aptitude show postgresql   grep State   But I guess you can just try to launch it with some flag like --version  that simply prints some info and exits   Updated using  service postgres status   Try   service postgres status if        -gt  0     then   echo  Not installed   else   echo  Intalled  fi

User · Answer

Well  all answersabove are good but not in all cases  Basically check the folder  etc postgresql  in most cases there will be one subfolder eg   etc postgresql 11   or  etc postgresql 12  which means that you have installed 11  or 12  version  however in many cases you may have many of such subfolders  so having them all means that all those versions had been ever installed and  could be in use     so be aware of this important trace  ps using Ubuntu 18 04

User · Answer

You may also check in  opt mount in following path  opt PostgresPlus 9 5AS bin

User · Answer

If you are running Debian Linux  or derivative  and if you have a postive return with  gt  which psql  then simply type psql -V  capital  V   and you will get a return like  psql  PostgreSQL  9 4 8

[linux] How can I check if PostgreSQL is installed or not via Linux script?

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