I'm writing a bash script and I want to redirect MySQL errors to a log file.
I had success with the below (ERROR 1045 (28000): Access denied for user... is being appended to the log file)
mysql -u user -pWrongpass -sN -e "query to update db;" 2>&1 | tee -a log
however, I'm not having success with this one. The error is displayed when I run the script but I don't see it in the log file.
result=$(mysql -u user -pWrongpass -sN "query to select from db;") 2>&1 | tee -a log
What's the correct syntax to put the result of a query into a variable while printing any potential error to the log file?
Thanks in advance and let me know if I'm not clear :)
You have to put the entire pipeline inside the command substitution.
result=$(mysql -u user -pWrongpass -sN "query to select from db;" 2>&1 |
tee -a log)
Since the output of mysql is piped to tee, it is the output of tee that you need to capture in result.
Related
I have a small down and dirty script to dump one of the tables all of a client's databases nightly:
#!/bin/bash
DB_BACKUP="/backups/mysql_backup/`date +%Y-%m-%d`"
DB_USER="dbuser"
DB_PASSWD="dbpass"
# Create the backup directory
mkdir -p $DB_BACKUP
# Remove backups older than 10 days
find /backups/mysql_backup/ -maxdepth 1 -type d -mtime +10 -exec rm -rf {} \;
# Backup each database on the system
for db in $(mysql --user=$DB_USER --password=$DB_PASSWD -e 'show databases' -s --skip-column-names|grep -viE '(staging|performance_schema|information_schema)');
do echo "dumping $db-uploads"; mysqldump --user=$DB_USER --password=$DB_PASSWD --events --opt --single-transaction $db uploads > "$DB_BACKUP/mysqldump-$db-uploads-$(date +%Y-%m-%d).sql";
done
Recently we've had some issues where some of the tables get corrupted, and mysqldump fails with the following message:
mysqldump: Got error: 145: Table './myDBname/myTable1' is marked as crashed and should be repaired when using LOCK TABLES
Is there a way for me to check if this happens in the bash script, and log the errors if so?
Also, as written would such an error halt the script, or would it continue to backup the rest of the databases normally? If it would halt execution is there a way around that?
Every program has an exit status. The exit status of each program is assigned to the $? builtin bash variable. By convention, this is 0 if the command was successful, or some other value 1-255 if the command was not successful. The exact value depends on the code in that program.
You can see the exit codes that mysqldump might issue here: https://github.com/mysql/mysql-server/blob/8.0/client/mysqldump.cc#L65-L72
You can check for this, and log it, output an error message of you choosing, exit the bash script, whatever you want.
mysqldump ...
if [[ $? != 0 ]] ; then
...do something...
fi
You can alternatively write this which does the same thing:
mysqldump ... || {
...do something...
}
The || means to execute the following statement or code block if the exit status of the preceding command is nonzero.
By default, commands that return errors do not cause the bash script to exit. You can optionally make that the behavior of the script by using this statement, and all following commands will cause the script to exit if they fail:
set -e
I am trying to take the output from a MySQL query in bash and use it in a bash variable, but it keeps coming up blank when used in the script, but works perfectly from the terminal. What's wrong here?
I've tried changing the way the statement is written and changing the name of the variable just in case it was somehow reserved. I've also done a significant amount of searching but it turns out if you but 'bash', 'blank', and 'variable' in the search it usually comes up with some version of how to test for blank variables which I already know how to do.
tempo=$(mysql -u "$dbuser" -p"$dbpass" -D "$database" -t -s -r -N -B -e "select user from example where user='$temp' > 0;")
printf "the output should be: $tempo" # This is a test statement
The end result should be that the $tempo variable should either contain a user name from the database or be blank if there isn't one.
I think there is some error with your sql statement at user = '$temp' > 0.
But to get the result from MySql you have to redirect the standard error (stderr) to the standard output (stdout), you should use 2>&1.
Most probably you will run into MySql error but try running this on terminal.
tempo=$((mysql -u "$dbuser" -p"$dbpass" -D "$database" -t -s -r -N -B -e "select user from example where user='$temp' > 0;") 2>&1)
The solution was to echo the result of the sql query like this:
tempo=$(echo $(mysql -u "$dbuser" -p"$dbpass" -D "$database" -s -N -B -e "select user from example where user='$username' > 0;"))
Now I'm left with logic issues but I think I can handle that.
I'm working on a simple bash script and one of the things it does is check whether a database already exists before moving on. It's simple enough code, but I'm getting a warning message whenever I try to run the script and I want to suppress that.
Here is the code:
if ! mysql -uroot -proot -e "use $NAME"; then
echo YES
else
echo NO
fi
So, as output, I get the following message when the if statement returns true:
ERROR 1049 (42000) at line 1: Unknown database 'database'
YES
How can I suppress that message? It doesn't stop the script from running, but I would prefer not to see it.
It simply tells you that the DB with the name database (which is apparently passed as a value of the $NAME variable) doesn't exist. Use the correct DB name and there'll be no warning.
To simply mute the warning redirect all the output to /dev/null as usual:
if ! mysql -uroot -proot -e "use $NAME" 2>&1 >/dev/null; then
echo YES
else
echo NO
fi
I want to remotely run the "show master status" command to get the bin log file and position.
mysql --user=<user> --password=<passwd> -e "show master status\G";
ERROR at line 1: Unknown command '\G'.
I want to get the result vertically and then use grep or awk to get the bin log file and position.
Any help is appreciated.
Thanks!
I am executing query from the command prompt with following command :
sqlcmd -U sa -P pal#143 -S .\SQLEXPRESS -i Employee.sql -o Employee.log
How can I get the result of execution to log file ?
I am not getting anything in the log file.
thanks