gzip already has gz suffix unchanged in the script - linux

Question

I have created a script to zip and move log files from one directory to another directory to free space. This is the script:
#!/bin/bash
logsDirectory="/test//logs/"
email=""
backupDirectory="/test/backup"
pid="/data/test/scripts/backup.pid"
usage=$(df | grep /data/logs | awk '{ print $2 }')
space=450000000
getBackup ()
{
if [[ ! -e $pid ]] then
if [[ $usage -le $space ]]
then
touch $pid
find $backupDirectory -mtime +15 -type f -delete;
for i in $(find $logsDirectory -type f -not -path "*/irws/*")
do
/sbin/fuser $i > /dev/null 2>&1
if [ $? -ne 0 ]
then
gzip $i
mv -v $i.gz $backupDirectory
else
continue
fi
done
[[ ! -z $email ]] && echo "Backup is ready" | mas"Backup" $email
rm -f $pid
fi
fi
}
getBackup
I am getting this error:
gzip: /data/logs/log01.log.gz already has .gz suffix -- unchanged
mv: cannot stat `/data/logs/log01.log.gz': No such file or directory
I got the error every time I ran the script in my DEV and PROD (CentOS servers) environments. To analyse it, I ran the same script in a VM (Ubuntu) in my laptop, and I don't get the error there.
My questions:
How can I prevent this error?
What I have done wrong in the script?

Answer 1

Your script contains a number of common clumsy or inefficient antipatterns. Here is a refactoring. The only real change is skipping any *.gz files.
#!/bin/bash
logsDirectory="/test//logs/"
email=""
backupDirectory="/test/backup"
pid="/data/test/scripts/backup.pid"
# Avoid useless use of grep -- awk knows how to match a regex
# Better still run df /data/logs
usage=$(df /data/logs/ | awk '{ print $2 }')
space=450000000
getBackup ()
{
# Quote variables
if [[ ! -e "$pid" ]]; then
if [[ "$usage" -le "$space" ]]; then
touch "$pid"
find "$backupDirectory" -mtime +15 -type f -delete;
# Exclude *.gz files
# This is still not robust against file names with spaces or wildcards in their names
for i in $(find "$logsDirectory" -type f -not -path "*/irws/*" -not -name '*.gz')
do
# Avoid useless use of $?
if /sbin/fuser "$i" > /dev/null 2>&1
then
gzip "$i"
mv -v "$i.gz" "$backupDirectory"
# no need for do-nothing else
fi
done
[[ ! -z "$email" ]] &&
echo "Backup is ready" | mas"Backup" "$email"
rm -f "$pid"
fi
fi
}
getBackup
With a slightly more intrusive refactoring, the proper fix to the find loop would perhaps look something like
find "$logsDirectory" -type f \
-not -path "*/irws/*" -not -name '*.gz' \
-exec sh -c '
for i; do
if /sbin/fuser "$i" > /dev/null 2>&1
then
gzip "$i"
mv -v "$i.gz" "$backupDirectory"
fi
done' _ {} +
where the secret sauce is to have find ... -exec + pass in the arguments to the sh -c script in a way which does not involve exposing the arguments to the current shell at all.

Answer 2

What I have done wrong in the script?
Your script tries to zip every file but the gzip command is rejecting files already zipped
How can I prevent this error?
Have the script check whether the file is zipped or not and only gzip if it corresponds (1). Alternatively, you could force re-compression even if it is already compressed (2).
Going with option number 1):
getBackup ()
{
if [[ ! -e $pid ]] then
if [[ $usage -le $space ]]
then
touch $pid
find $backupDirectory -mtime +15 -type f -delete;
for i in $(find $logsDirectory -type f -not -path "*/irws/*")
do
/sbin/fuser $i > /dev/null 2>&1
if [ $? -ne 0 ]
then
if [[ $i =~ \.gz$ ]]
# File is already zipped
mv -v $i $backupDirectory
else
gzip $i
mv -v $i.gz $backupDirectory
fi
else
continue
fi
done
[[ ! -z $email ]] && echo "Backup is ready" | mas"Backup" $email
rm -f $pid
fi
fi
}