My log files are getting dumped with following message while running shell scripts using some underlying MySQL commands.

Here is the message:

"Warning: Using a password on the command line interface can be insecure."

To stop these messages, I am using the following job definition.


run_wrapper.sh |grep -v "Warning: Using a password" > output.log 2>&1

This worked but the MySQL errors are not being logged to output.log.

If I change the definition like the following, then MySQL errors start appearing if any

run_wrapper.sh > output.log 2>&1

So the question is how to suppress the warning messages and also report SQL errors in log files using only the cron definition?

  • probably you should use run_wrapper.sh >> output.log 2>&1 – Rahul Jul 5 '16 at 9:17
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    I'm not following. Where would you want error/warnings to go and where would you want output to go, and what would you want to throw away? What is generating the password warning and why do you have errors in the MySQL that you don't want to fix? – Kusalananda Jul 5 '16 at 9:38
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    mysql prints that warning when you use the -p option on the command line. Instead of fixing it (e.g. by creating a ~/.my.cnf with 600 perms) the OP wants to just ignore and discard the warning (and only that warning, not all of stderr) – cas Jul 5 '16 at 13:10

In your bash script, edit it at top

export MYSQL_PWD=yourdbpassword

and mysql query like: mysql -u username -h host db -e "statement"

Reference: From answer posted at Stackoverflow. Other answers can also be followed.


It looks like you're missing the stderr redirection from run_wrapper.sh itself, so the errors aren't going through the grep and thence to the log file.

Try this instead if you're happy to have both stdout and sdterr written to your logfile

run_wrapper.sh 2>&1 | grep -v "Warning: Using a password" > output.log

Or if you want only the errors written to the logfile, and stdout left writing to the calling terminal, try this

( run_wrapper.sh 2>&1 1>&3 | grep -v "Warning: Using a password" > output.log ) 3>&1

search for a line in your wrapper similar to

mysql -u<username> -p<some_password> -hlocalhost -D<database_name> 

and change to

export MYSQL_PWD=<some_password> ; mysql -u<username> -hlocalhost -D<database_name> 

this solves the source of the warning.


Try this:

> "$lf"   # first truncate/create the logfile.
run_wrapper.sh >> "$lf" 2> >(grep -v "Warn.*passw.*insec" >> "$lf")

Redirects stderr via Process Substitution to grep -v ..., and output from that is appended with >> to output.log

You probably want to use (GNU) grep's --line-buffered option as well as -v to make sure error output isn't delayed.

If post-processing the log file is an acceptable option for you, you could just delete the unwanted "Warning: " line(s) from the log file after run_wrapper.sh has finished.

The following shell script fragment saves the timestamp (in $ts) of the log file (in $lf) before running sed -i and restores it afterwards:


run_wrapper.sh >& "$lf"

ts=$(date -r "$lf" '+%Y%m%d%H%M.%S')
sed -i -e '/Warning: Using a password/d' "$lf"
touch -t "$ts" "$lf"

If you need to preserve the inode of the log file (e.g. because it has hard links), use ed rather than sed:

ts=$(date -r "$lf" '+%Y%m%d%H%M.%S')
printf "%s\n" 'g/Warning: Using a password/d' w | ed -s "$lf"
touch -t "$ts" "$lf"
  • Thanks for the response. I have tried the suggested option like below – jagadish puvvada Jul 6 '16 at 5:13
  • sed option creates blank lines and we need to remove them also and it changes file timestamp also – jagadish puvvada Jul 8 '16 at 5:06
  • The post-process-with-sed option also changes the inode as well as the timestamp - that's normal for -i (and most forms of "in-place" editing"). If run immediately afterwards, it should only be microseconds or seconds different, depending on logfile size of course. But there's no way a d (delete line) command in sed will create a blank line - what exactly do you mean by that? – cas Jul 8 '16 at 5:15
  • @jagadishpuvvada sed option now saves and restores output.log's timestamp. – cas Jul 8 '16 at 12:06

Try adding this to the end of your command:

/dev/null 2>&1

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