I'm trying to get a list of database names using the psql command. So far I have:
psql -h example.com -U backup -c '\l'
This however gives me the results in a table-like format. I ONLY want the table names (one on each line). How would I accomplish this?
This does it:
psql -h example.com -U backup -t -A -c "SELECT datname FROM pg_database WHERE datname <> ALL ('{template0,template1,postgres}')"
Using the system catalog pg_database.
Read the manual about psql.
I don't think you can use \l for that.
But the following should do it:
psql -h example.com -U backup -t -c "select datname from pg_database"
\t turns off the header and the other "noise". And the select statement only returns the database name.
Not sure if you need to use single quotes or double quotes for the SQL statement - on my Windows console I had to use double quotes.
Related
I want to export a random entry of my database into a file with the command
SELECT * FROM my_table ORDER BY RANDOM() LIMIT 1 \g /path/file;
This query works if I enter it in my db terminal, but I want to us this query with a bash script but then I get the error: syntax error at or near "\g"
My bash script looks like this:
PGPASSWORD=*** psql -U user -d db_name -h localhost -p port -t -c "SELECT * FROM my_table ORDER BY RANDOM() LIMIT 1 \g /path/file"
Bash is interpreting the string and trying to interpolate it. Probably, escaping the backslash will solve your problem.
PGPASSWORD=*** psql -U user -d db_name -h localhost -p port -t -c "SELECT * FROM my_table ORDER BY RANDOM() LIMIT 1 \\g /path/file"
A SQL statement terminated by \g is not supported by the -c command switch. Per documentation of -c:
-c command
...
command must be either a command string that is completely parsable by the server (i.e., it contains no psql-specific features), or a single backslash command. Thus you cannot mix SQL
and psql meta-commands with this option
To redirect the results to a file, there are several options:
shell redirection: psql [other options] -Atc 'SELECT...' >/path/to/data.txt
-A is to switch to unaligned mode (no space fillers to align columns).
put the SQL part in a heredoc text instead of the command line:
psql [options] <<EOF
SELECT ... \g /path/to/file
EOF
This form has the advantage that multiline statements or multiple statements are supported directly.
\copy of the query. Be aware that COPY to a FILE is different: it creates the file on the server with the permissions of postgres and requires being a database superuser. COPY TO STDOUT works too but is not better than SELECT concerning the redirection.
I found a solution for my script, and now it works.
#!/bin/bash
RANDOM_NUMBER=0
while true
do
for i in `seq 1`
do
RANDOM_NUMBER=$(($RANDOM % 100000))
echo $RANDOM_NUMBER
PGPASSWORD=*** psql -U user_name -d db_name -h localhost -p PORT -c
"INSERT INTO numbers (number) VALUES ('$RANDOM_NUMBER');"
done
sleep 10
for i in `seq 1`
do
PGPASSWORD=*** psql -U user_name -d db_name -h localhost -p PORT -c
"DELETE FROM numbers WHERE id = (SELECT id FROM numbers ORDER BY RANDOM() LIMIT 1);"
done
done
I have the following snippet of code in a bash script:
psql -U ppd ppd -h $remote_server -t -c "copy (SELECT CASE WHEN DATE_TRUNC('MONTH', ABSTIME(start_ts)) = DATE_TRUNC('MONTH', CURRENT_DATE) THEN 'current' ELSE DATE_TRUNC('MONTH', ABSTIME(start_ts))::DATE::TEXT END,
id,
status,
class,
dir,
volid,
f_user,
t_user,
ABSTIME(start_ts),
ABSTIME(end_ts),
elapsed,
callid, f_uri, t_uri, lcr_tag
FROM ppd_widgets) to '/tmp/"$server".db' With CSV DELIMITER ',';"
scp -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null "root#$server:/tmp/$server.db" "$dir/"
I'd like to know if there's a way to do it in one shot - aka instead of creating a csv file on the remote server and then copy it over, can I select the records and display in csv format?
Then I could do something like this:
psql -U ppd ppd -h $remote_server -t -c "select that returns in csv style" >> save_to_local.csv
Any tips / suggestions on how I can do this?
Use psql's \copy function (not PostgreSQL's copy function)
This lets you load or save files locally
Example:
psql -c "\copy (select ...) to 'local-file.csv'"
I need to drop a mysql database directlly from a script.
I create the file ~/.my.cnf and chmod 600.
[client]
user = "**************"
password = "*********"
safe-updates
My script includes this :
CMD4="echo 'DROP DATABASE db_test;' | mysql"
curl -fs -- "$URL" | grep -q -- "$WORD1" && $CMD4
I can´t execute the command I just get this output:
'DROP DATABASE db_test;' | mysql
The database is not dropped.
What´s wrong with it?
Thanks
I think you should enclose the below statement in Grave accent (``) instead of double quotes ("") where you are initializing the value of CMD4 on the both
echo 'DROP DATABASE db_test;' | mysql
You can eliminate the pipe using mysql -Bse 'expression'. So in your case, with the correct ~/.my.cnf setting you can simply do:
mysql -Bse "drop database db_test"
You also have the full range of mysql options as well. i.e. mysql -h somehost -u someuser -p pass -Bse "expression"
Please, don't use variable to store code. Use function instead:
function dropdb {
echo 'DROP DATABASE db_test;' | mysql # aren't you missing some arguments here?
# like `-u username -p db`
}
curl -fs -- "$URL" | grep -q -- "$WORD1" && dropdb
I'm going crazy while trying to insert bash-variables in a psql commands as connection paramters as well as variables in the command itself. The following example works properly:
psql -U postgres -h localhost -p 5432 -c "CREATE DATABASE testdb WITH ENCODING='UTF8' OWNER=postgres TABLESPACE=pg_default TEMPLATE=template_postgis CONNECTION LIMIT=-1;"
Now I'm trying to exchange each parameter through a variable, which is held in special config-file.
Non-working example:
dbserver=localhost
dbport=5432
dbowner=postgres
dbname=testdb
dbtemplate=template_postgis
dbtablespace=pg_default
psql -U '$dbowner' -h '$dbserver' -p '$dbport' -c "CREATE DATABASE '$dbname' WITH ENCODING='UTF8' OWNER='§dbowner' TABLESPACE='$dbtablespace' TEMPLATE='$dbtemplate'
CONNECTION LIMIT=-1;"
I've tried several quotings, backquotes and escape-slashes already but smhow it still won't work.
Thanks in advance, knutella
Use double quotes ("). Single quotes (') does not interpret shell variables inside.
Try it
echo '$USER' "$USER"
See man bash.
This works... most of the quotes are not needed:
psql -U $dbowner -h $dbserver -p $dbport -c "CREATE DATABASE $dbname WITH ENCODING='UTF8' OWNER=$dbowner TABLESPACE=$dbtablespace TEMPLATE=$dbtemplate CONNECTION LIMIT=-1;"
How to atore a scalar postgresql-value on a bash-variable like in script below?
dbname="testlauf"
username="postgres"
vartest='psql -c -d $dbname -U $username -h localhost -p 5432 "SELECT gid FROM testtable WHERE aid='1';"'
echo "$vartest"
I tried several different writings, but nothing seems to work. Thanks in advance.
Put the -c option just before its argument - the query. Mind also using the additional -t option to get just the tuple value. And of course, use the backticks (`) operator.
Using the -X option is also recommended, as sometimes a .psqlrc file might add some redundant output, as well as the -A option, which disables column aligning (whitespaces).
In order to skip NOTICE or other additional messages, include the -q flag.
vartest=`psql -d $db -U $user -AXqtc "SELECT gid FROM testtable WHERE aid='1'"`
Using -t option or --tuples-only will give you the rows only, so it will easier to store them in array variable (if the result from query more than one)
vartest =(`psql -t -d $dbname -U $username -c "SELECT gid FROM testtable WHERE aid='1';"`)
echo $vartest
example:
query result
ubuntu#ratnakri:~$ psql -h localhost -p 5432 -t -U postgres -d postgres -c "select slot_name from pg_replication_slots"
barman
barman2
make it into array variable
ubuntu#ratnakri:~$ RESULT=(`psql -h localhost -p 5432 -t -U postgres -d postgres -c "select slot_name from pg_replication_slots"`)
ubuntu#ratnakri:~$ echo ${RESULT[0]}
barman
ubuntu#ratnakri:~$ echo ${RESULT[1]}
barman2