[SOLVED] using getopts with flags to backup cronjobs

suicidaleggroll · 06-22-2016, 10:11 AM

Still lots of problems...you're looping over all users when one was provided, you didn't close out one of your for loops, your method of grabbing the user name when one was not provided won't work, and your method of restoring from backup is still invalid. Please see my previous post, and please pay attention to the first section, where you ignore the script, shut it down, close it out, and focus SOLELY on the backup and restore commands (namely restore).

Remember, everything you can put in a script, you can also run by itself on the shell. That's all a script is, a collection of shell commands.

You also need to stick an echo in front of all of your crontab calls until you get this figured out. Running arbitrary commands with unknown arguments and invalid redirection as root is GOING to break something. I hope this is a disposable VM you're testing on.

michaelk · 06-22-2016, 10:44 AM

In addition, to help you see what your script is actually doing add the command
set -xv

Right below your shebang i.e. #!/bin/bash

$HOSTNAME is the correct environment variable. linux is case sensitive.

linuxnewbie0101 · 06-22-2016, 12:24 PM

new updated script

Code:

#!/bin/bash
set -xv

bkuplocation="/systems/homes/cronjobs_bk/$hostname"
cron_source="/var/spool/cron/crontabs/*"
hostname=$(hostname -s)

#Help function
function show_help {
  echo " Command line switches -m is required, -p & -u are optional."
  echo " -m  --Sets the value for option to backup or restore (backup/restore)."
  echo " -p  --(OPTIONAL) Sets the path to backup from and restore to."
  echo " -u  --(OPTIONAL) Sets the user jobs to backup."
  echo " -h  --Displays this help message. No further functions are performed."
  exit 1
}

#Check the number of arguments. If none are passed, print help and exit.
numargs=$#
if [ $numargs -eq 0 ]; then
  show_help
fi

# Start getopts code
while getopts m:p?u?h? options; do
  case $options in
    m) 
      method=$optarg
      ;;
    p) 
      location=$optarg
      ;;
    u)
      user=$optarg
      ;;
    h)
      show_help
      ;;
  \?) echo -e "Option $optarg not allowed."
      show_help
      ;;
  esac
done

case $method in
  backup)
    if [ ! -d "$bkuplocation" ]; then
	mkdir "$bkuplocation"
    fi
    if [[ -z "$location" && -z "$user" ]]; then
      for i in "$cron_source"; do 
        echo "crontab -l -u $i > $bkuplocation/$i"
      done
    elif [[ ! -z "$location" && ! -z "$user" ]]; then
        echo "crontab -l -u $user > $location/$user"
    elif [[ -z "$location" && ! -z "$user" ]]; then
        echo "crontab -l -u $user > $bkuplocation/$user"
    elif [[ ! -z "$location" && -z "$user" ]]; then
      for i in "$cron_source"; do 
        echo "crontab -l -u $i > $location/$i"
      done
    else 
      show_help
    fi
  ;;

  restore)
    if [ ! -d "$bkuplocation" ]; then
	echo "no backup found for $host"
    fi
    if [[ -z "$location" && -z "$user" ]]; then
      for i in "$bkuplocation"; do
        echo "crontab $i"
      done  
    elif [[ ! -z "$location" && ! -z "$user" ]]; then
        echo "crontab $user < $location/$user"
    elif [[ ! -z "$location" && -z "$user" ]]; then
      for i in "$location"; do 
        echo "crontab $i < $location"
      done
    elif [[ -z "$location" && ! -z "$user" ]]; then
        echo "crontab $user < $bkuplocation/$user"
    else
      show_help
    fi
  ;;
esac

shift $((OPTIND-1))

exit 0

however, i am getting the following output, to me it seems fine? any thoughts?

Code:

$ sudo ./getopts.sh -m backup

bkuplocation="/systems/homes/cronjobs_bk/$hostname"
+ bkuplocation=/systems/homes/cronjobs_bk/
cron_source="/var/spool/cron/crontabs/*"
+ cron_source='/var/spool/cron/crontabs/*'
hostname=$(hostname -s)
hostname -s
++ hostname -s
+ hostname=mysql11

#Help function
function show_help {
  echo " Command line switches -m is required, -p & -u are optional."
  echo " -m  --Sets the value for option to backup or restore (backup/restore)."
  echo " -p  --(OPTIONAL) Sets the path to backup from and restore to."
  echo " -u  --(OPTIONAL) Sets the user jobs to backup."
  echo " -h  --Displays this help message. No further functions are performed."
  exit 1
}

#Check the number of arguments. If none are passed, print help and exit.
numargs=$#
+ numargs=2
if [ $numargs -eq 0 ]; then
  show_help
fi
+ '[' 2 -eq 0 ']'

# Start getopts code
while getopts m:p?u?h? options; do
  case $options in
    m) 
      method=$optarg
      ;;
    p) 
      location=$optarg
      ;;
    u)
      user=$optarg
      ;;
    h)
      show_help
      ;;
  \?) echo -e "Option $optarg not allowed."
      show_help
      ;;
  esac
done
+ getopts 'm:p?u?h?' options
+ case $options in
+ method=
+ getopts 'm:p?u?h?' options

case $method in
  backup)
    if [ ! -d $bkuplocation ]; then
	mkdir $bkuplocation
    fi
    if [[ -z $location && -z $user ]]; then
      for i in $cron_source; do 
        crontab -l -u $i > "$bkuplocation/$i"
      done
    elif [[ ! -z $location && ! -z $user ]]; then
        crontab -l -u $user > "$location/$user"
    elif [[ -z $location && ! -z $user ]]; then
        crontab -l -u $user > "$bkuplocation/$user"
    elif [[ ! -z $location && -z $user ]]; then
      for i in $cron_source; do 
        crontab -l -u $i > "$location/$i"
      done
    else 
      show_help
    fi
  ;;

  restore)
    if [ ! -d $bkuplocation ]; then
	echo "no backup found for $host"
    fi
    if [[ -z $location && -z $user ]]; then
      for i in $bkuplocation; do
        crontab $i
      done  
    elif [[ ! -z $location && ! -z $user ]]; then
        crontab $user < "$location/$user"
    elif [[ ! -z $location && -z $user ]]; then
      for i in $location; do 
        crontab $i < $location
      done
    elif [[ -z $location && ! -z $user ]]; then
        crontab $user < "$bkuplocation/$user"
    else
      show_help
    fi
  ;;
esac
+ case $method in

shift $((OPTIND-1))
+ shift 2

exit 0
+ exit 0

suicidaleggroll · 06-22-2016, 12:37 PM

You can get rid of half of your elif statements if you add one if before your "case $method in":

Code:

if [ -z $location ]; then
  location=$bkuplocation
fi

Then just use $location from then on.

As for your problem, optarg needs to be capitalized:
method=$OPTARG
and so on

Your syntax for optstring is also incorrect, it should be:

Code:

while getopts m:p:u:h options; do

The very first step in debugging a program like this should be to print out all of the variables you think you're setting and verify they are what you think they are. "echo" is your friend, use it.

For example, you still aren't passing the user correctly to crontab when $user is not set...$i does not contain what you think it contains.

Comment out all of your calls to crontab and stick some echos in there to make sure you're going to call what you think you're going to call before actually doing it and potentially screwing something up. Passing the wrong argument to crontab can permanently wipe out a user's cron. Nobody develops scripts the way you're doing it here, entering seemingly random commands and arguments you don't understand without knowing variable contents or verifying any of it, then running it as root, where a small syntax error could cause MAJOR damage to the system. It's a recipe for disaster. As I said before, I sure hope this is a disposable VM you're testing on and not a live system, and that you've already made backups of ALL of the user crontabs in a safe location (that's not referenced anywhere in this script).

linuxnewbie0101 · 06-22-2016, 03:17 PM

im hitting the wall....

michaelk · 06-22-2016, 03:24 PM

Debugging can be "fun". Did you fix getopts and all the $OPTARG as indicated above?

Where are you stuck?

linuxnewbie0101 · 06-22-2016, 03:44 PM

so this is the new updated script. however, when i debug the errors follows. thanks for all you guys help.

Code:

#!/bin/bash
set -xv

bkuplocation="/systems/homes/cronjobs_bk"
cron_source="/var/spool/cron/crontabs"
hostname=$(hostname -s)

#Help function
function show_help {
  echo " Command line switches -m is required, -p & -u are optional."
  echo " -m  --Sets the value for option to backup or restore (backup/restore)."
  echo " -p  --(OPTIONAL) Sets the path to backup from and restore to."
  echo " -u  --(OPTIONAL) Sets the user jobs to backup."
  echo " -h  --Displays this help message. No further functions are performed."
  exit 1
}

#Check the number of arguments. If none are passed, print help and exit.
numargs=$#
if [ $numargs -eq 0 ]; then
  show_help
fi

# Start getopts code
while getopts m:puh options; do
  case $options in
    m) 
      method=$OPTARG
      ;;
    p) 
      location=$OPTARG
      ;;
    u)
      user=$OPTARG
      ;;
    h)
      show_help
      ;;
  \?) echo -e "Option $OPTARG not allowed."
      show_help
      ;;
  esac
#done

cd $cron_source

case $method in
  backup)
    if [[ ! -d "$bkuplocation" ]]; then
	mkdir "$bkuplocation"
    fi
    if [[ -z "$location" && -z "$user" ]]; then
      cd $cron_source
      for i in *; do 
        "crontab -l -u $i > $bkuplocation/$i"
      done
    elif [[ ! -z "$location" && ! -z "$user" ]]; then
        "crontab -l -u $user > $location/$user"
    elif [[ -z "$location" && ! -z "$user" ]]; then
        "crontab -l -u $user > $bkuplocation/$user"
    elif [[ ! -z "$location" && -z "$user" ]]; then
      for i in *; do 
        "crontab -l -u $i > $location/$i"
      done
    else 
      show_help
    fi
  ;;

  restore)
    if [[ ! -d "$bkuplocation" ]]; then
	echo "no backup found for $host"
    fi
    if [[ -z "$location" && -z "$user" ]]; then
      for i in *; do
        "crontab $i"
      done  
    elif [[ ! -z "$location" && ! -z "$user" ]]; then
        "crontab $user < $location/$user"
    elif [[ ! -z "$location" && -z "$user" ]]; then
      for i in *; do 
        "crontab $i < $location"
      done
    elif [[ -z "$location" && ! -z "$user" ]]; then
        "crontab $user < $bkuplocation/$user"
    else
      show_help
    fi
  ;;
esac

done

shift $((OPTIND-1))

exit 0

debug output:

Code:

~$ sudo ./getopts.sh -m backup

bkuplocation="/systems/homes/cronjobs_bk"
+ bkuplocation=/systems/homes/cronjobs_bk
cron_source="/var/spool/cron/crontabs"
+ cron_source=/var/spool/cron/crontabs
hostname=$(hostname -s)
hostname -s
++ hostname -s
+ hostname=mysql11

#Help function
function show_help {
  echo " Command line switches -m is required, -p & -u are optional."
  echo " -m  --Sets the value for option to backup or restore (backup/restore)."
  echo " -p  --(OPTIONAL) Sets the path to backup from and restore to."
  echo " -u  --(OPTIONAL) Sets the user jobs to backup."
  echo " -h  --Displays this help message. No further functions are performed."
  exit 1
}

#Check the number of arguments. If none are passed, print help and exit.
numargs=$#
+ numargs=2
if [ $numargs -eq 0 ]; then
  show_help
fi
+ '[' 2 -eq 0 ']'

# Start getopts code
while getopts :m:p:u:h options; do
  case $options in
    m) 
      method=$OPTARG
      ;;
    p) 
      location=$OPTARG
      ;;
    u)
      user=$OPTARG
      ;;
    h)
      show_help
      ;;
  \?) echo -e "Option $OPTARG not allowed."
      show_help
      ;;
  esac
#done

#if [ -z $location ]; then
#  location=$bkuplocation
#fi

cd $cron_source

case $method in
  backup)
    if [ ! -d "$bkuplocation" ]; then
	mkdir "$bkuplocation"
    fi
    if [[ -z "$location" && -z "$user" ]]; then
      cd $cron_source
      for i in *; do 
        "crontab -l -u $i > $bkuplocation/$i"
      done
    elif [[ ! -z "$location" && ! -z "$user" ]]; then
        "crontab -l -u $user > $location/$user"
    elif [[ -z "$location" && ! -z "$user" ]]; then
        "crontab -l -u $user > $bkuplocation/$user"
    elif [[ ! -z "$location" && -z "$user" ]]; then
      for i in *; do 
        "crontab -l -u $i > $location/$i"
      done
    else 
      show_help
    fi
  ;;

  restore)
    if [ ! -d "$bkuplocation" ]; then
	echo "no backup found for $host"
    fi
    if [[ -z "$location" && -z "$user" ]]; then
      for i in *; do
        "crontab $i"
      done  
    elif [[ ! -z "$location" && ! -z "$user" ]]; then
        "crontab $user < $location/$user"
    elif [[ ! -z "$location" && -z "$user" ]]; then
      for i in *; do 
        "crontab $i < $location"
      done
    elif [[ -z "$location" && ! -z "$user" ]]; then
        "crontab $user < $bkuplocation/$user"
    else
      show_help
    fi
  ;;
esac

done
+ getopts :m:p:u:h options
+ case $options in
+ method=backup
+ cd /var/spool/cron/crontabs
+ case $method in
+ '[' '!' -d /systems/homes/cronjobs_bk ']'
+ [[ -z '' ]]
+ [[ -z '' ]]
+ cd /var/spool/cron/crontabs
+ for i in '*'
+ 'crontab -l -u mysql > /systems/homes/cronjobs_bk/mysql'
./getopts.sh: line 59: crontab -l -u mysql > /systems/homes/cronjobs_bk/mysql: No such file or directory
+ for i in '*'
+ 'crontab -l -u root > /systems/homes/cronjobs_bk/root'
./getopts.sh: line 59: crontab -l -u root > /systems/homes/cronjobs_bk/root: No such file or directory
+ getopts :m:p:u:h options

shift $((OPTIND-1))
+ shift 2

exit 0
+ exit 0

now if i ran these manually, it works. ?????scratch my head?????

Code:

+ 'crontab -l -u mysql > /systems/homes/cronjobs_bk/mysql'
./getopts.sh: line 59: crontab -l -u mysql > /systems/homes/cronjobs_bk/mysql: No such file or directory
+ for i in '*'
+ 'crontab -l -u root > /systems/homes/cronjobs_bk/root'
./getopts.sh: line 59: crontab -l -u root > /systems/homes/cronjobs_bk/root: No such file or directory

suicidaleggroll · 06-22-2016, 03:53 PM

Hint:

Code:

$ echo 5 > testfile
$ cat testfile
5
$ "echo 5 > testfile"
bash: echo 5 > testfile: command not found...

keefaz · 06-22-2016, 04:00 PM

Change #done -> done (uncomment it) near line 43

linuxnewbie0101 · 06-22-2016, 04:01 PM

Quote:

Originally Posted by suicidaleggroll

Hint:

Code:

$ echo 5 > testfile
$ cat testfile
5
$ "echo 5 > testfile"
bash: echo 5 > testfile: command not found...

OMFG suicidaleggroll you are freaking awesome.

TYTYTYTYTY

michaelk · 06-22-2016, 04:08 PM

Quote:

Originally Posted by keefaz

Change #done -> done (uncomment it) near line 43

The OP may never figure it out... and comment out the last done.

keefaz · 06-22-2016, 04:24 PM

Quote:

Originally Posted by michaelk

The OP may never figure it out... and comment out the last done.

Lol, true I overlooked the end of script,

Line 43: done -> comment out
Line 92: done -> delete or comment

linuxnewbie0101 · 06-22-2016, 04:27 PM

Quote:

Originally Posted by keefaz

Lol, true I overlooked the end of script,

Line 43: done -> comment out
Line 92: done -> delete or comment

keefaz, TY for all your help as well.

This is the first time that i really post on this forum and so far it had blowed my mind.

Thank you all for helping.

keefaz · 06-22-2016, 05:02 PM

For my part, with serious scripts I like to make functions, like your show_help function.
That helps to narrow debugging, I mean to know what part doesn't work

In this script, I would have done:

function getScriptOptions()
function setBackupDir()
function backup()
function restore()

linuxnewbie0101 · 06-23-2016, 09:55 AM

Quote:

Originally Posted by keefaz

For my part, with serious scripts I like to make functions, like your show_help function.
That helps to narrow debugging, I mean to know what part doesn't work

In this script, I would have done:

function getScriptOptions()
function setBackupDir()
function backup()
function restore()

possible to provide an example of functions?