script from cron doesn't run - bash

Question

I have a script:
-rwx------. 1 root root 135 Oct 15 12:00 /backup/purge.sh
#!/bin/bash
volume=`echo "list volumes" | bconsole|grep -i "Append\|Full"|awk '{print $4}'`
echo "purge volume=$volume yes" | bconsole
If I run it manually it runs.
If I put the script to crontab it doesn't run, however the log says it ran.
Oct 15 16:07:01 sdfdsfdsf CROND[36326]: (root) CMD (/backup/purge.sh)
The schedule:
07 16 * * * /backup/purge.sh
If I run manually:
/backup/purge.sh
Connecting to Director weewr:9101
1000 OK: 1 werewrewrewr Version: 7.0.5 (28 July 2014)
Enter a period to cancel a command.
purge volume=Vol-0001 yes
This command can be DANGEROUS!!!
It purges (deletes) all Files from a Job,
JobId, Client or Volume; or it purges (deletes)
all Jobs from a Client or Volume without regard
to retention periods. Normally you should use the
PRUNE command, which respects retention periods.
Automatically selected Catalog: MyCatalog
Using Catalog "MyCatalog"
1 File on Volume "Vol-0001" purged from catalog.
There are no more Jobs associated with Volume "Vol-0001". Marking it purged.

Answer 1

bconsole hasn't been in the PATH so I used full path for the bconsole command like this:
!/bin/bash
volume=echo "list volumes" | /sbin/bconsole|grep -i "Append\|Full"|awk '{print $4}'
echo "purge volume=$volume yes" | /sbin/bconsole