bash returns ambiguous redirect with date in filename

rstoutmna · 01-11-2005, 08:36 AM

Hi I was wondering if anyone knew why in bash when I use cron to do a mysqldump and include the date in the filename I get an error on all times between midnight and 10AM

Here is my script:

#!/bin/bash

mysqldump --all-databases > /mnt/serv/mysqldump_$(date '+%Y-%m-%d-%k-%M').sql
mysqldump --all-databases > /home/nsuser/mysqlbackup/mysqldump_$(date '+%Y-%m-%d-%k-%M').sql

The email response sent to my root account is below

/etc/cron.hourly/mysqldump:

/etc/cron.hourly/mysqldump: line 3: /mnt/serv/mysqldump_$(date '+%Y-%m-%d-%k-%M').sql: ambiguous redirect

/etc/cron.hourly/mysqldump: line 4: /home/nsuser/mysqlbackup/mysqldump_$(date '+%Y-%m-%d-%k-%M').sql: ambiguous redirect

And this works without a problem between 10AM and 11pm.
Any input is appreciated.

homey · 01-11-2005, 08:54 AM

Maybe you would have better luck creating the filename first, then calling that variable later in the script. Like this : filename=`date '+%m%d%y'`
Note: those are backticks ( ` ) and single quotes ( ' )

Here is an example

Code:

#!/bin/bash
filename=`date '+%m%d%y'`
/bin/tar -cvzf /mnt/backup/${filename}.tar.gz . \
> /mnt/backup/${filename}.log \
2> /mnt/backup/${filename}err.log

bigearsbilly · 01-11-2005, 10:11 AM

clue:
midnight = 00
ten = 10

1 am = 1

you are probably getting spaces for the single digits in the filename.
like

Code:

mysqldump --all-databases > /home/nsuser/mysqlbackup/mysqldump_2005-01- 1.sql

homey is right, construct the file name first.

if there are spaces you will need to get rid of them
as they'll mess up your 'sort' of course.

you can use typeset (in ksh maybe bash?) to pad them with zeroes

e.g:

Code:

>typeset -Z5 num
>num=3          
>echo $num      
00003

hint: don't hardcode filenames and multiply redirect.
redirect once.

either use

Code:

# all lines after this default to the output file
exec  2>&1 > $OUTFILE_NAME

or put them in a function and redirect the function like

Code:

# function definition
do_it()
{
   blah
   blah/blah
   echo done
}

do_it 2>&1 > $OUTFILE

never hardcode file names or such like. Use a variable that you can change in one place.

rstoutmna · 01-11-2005, 02:05 PM

I changed my script and am going to check on it tomorrow. I am pretty sure both of you are correct. Thanks so much for your help I will post here tomorrow whether it did in fact work. --Thanks again

kees-jan · 01-12-2005, 04:50 AM

If you don't want to wait till tomorrow to do small tests, you can locally modify your timezone in the TZ environment variable to obtain different times. For example:

Code:

$ env TZ=GMT+5 date '+%Y-%m-%d-%k-%M'
2005-01-12- 5-47

There is indeed a space in the name you are using.

Groetjes,

Kees-Jan

rjmx · 09-13-2011, 07:37 PM

I know it's been a long time, but the current version of GNU date (date (GNU coreutils) 8.5) allows the use of '%H' to give a two-digit hour (with leading zeroes if necessary). Replacing '%k' in the original poster's code with '%H' should fix the problem.
Don't know if %H was available back in 2005, though.