pb nagios bash script null result in if - bash

I have a problem with a bash script in Nagios. this is a script to get the space disk. When I used an IF section it returns (null) and when I don't set the variable in IF section, nagios display the variable correctly. I tried to run the script with nagios user and the result is good. Ex:
TOTAL=`/srv/eyesofnetwork/nagios/plugins/check_nt -H $2 -p 12489 -s "" -v USEDDISKSPACE -l $4 |awk -F"-" '{print $2}' |awk '{print $2}'`
if [ $TOTAL -gt 2 ] && [ $TOTAL -le 99 ];then
RUN=`/srv/eyesofnetwork/nagios/plugins/check_nrpe -H $2 -c ``check_drivesize -a drive=$4 'warning=free<2G' 'critical=free<1G' show-all 'perf-config=*(unit:G)' top-syntax='${status} : ${problem_list}'`
VAR=$(echo $RUN |grep -i ok |wc -l)
if [ $VAR -eq 1 ];then
echo "$RUN"
exit 0
fi
I tried all possibilities (for me..), with "", with '', with nothing. The variable $RUN is not displayed.
Thanks

Finally, I wrote a script in python and now it works correctly

Related

Grep inside bash script not finding item

I have a script which is checking a key in one file against a key in another to see if it exists in both. However in the script the grep never returns anything has been found but on the command line it does.
#!/bin/bash
# First arg is the csv file of repo keys separated by line and in
# this manner 'customername,REPOKEY'
# Second arg is the log file to search through
log_file=$2
csv_file=$1
while read line;
do
customer=`echo "$line" | cut -d ',' -f 1`
repo_key=`echo "$line" | cut -d ',' -f 2`
if [ `grep "$repo_key" $log_file` ]; then
echo "1"
else
echo "0"
fi
done < $csv_file
The CSV file is formatted as follows:
customername,REPOKEY
and the log file is as follows:
REPOKEY
REPOKEY
REPOKEY
etc
I call the script by doing ./script csvfile.csv logfile.txt
Rather then checking output of grep command use grep -q to check its return status:
if grep -q "$repo_key" "$log_file"; then
echo "1"
else
echo "0"
fi
Also your script can be simplified to:
log_file=$2
csv_file=$1
while IFS=, read -r customer repo_key; do
if grep -q "$repo_key" "$log_file"; then
echo "1"
else
echo "0"
fi
done < "$csv_file"
use the exit status of the grep command to print 1 or 0
repo_key=`echo "$line" | cut -d ',' -f 2`
grep -q "$repo_key" $log_file
if [ $? -eq 1 ]; then
echo "1"
else
echo "0"
fi
-q supresses the output so that no output is printed
$? is the exit status of grep command 1 on successfull match and 0 on unsuccessfull
you can have a much simpler version as
grep -q "$repo_key" $log_file
echo $?
which will produce the same output

Bash Syntax error in conditional expression

I'm trying to make a simple bash script that will iterate through a text file containing IP addresses,
ping them one time, and see if they are alive or not.
This is my work so far:
#!/bin/bash
for ip in $(cat ips.txt); do
if [[ "1" == "$(ping -c 1 $ip | grep 'packets transmitted' | cut -d ' ' -f 4)"]]
echo $ip
fi
done
Any Suggestions?
Thanks!
This seems to work:
#!/bin/bash
for ip in $(cat ips.txt); do
if [ "1" == "$(ping -c 1 $ip | grep 'packets transmitted' | cut -d ' ' -f 4)" ]; then
echo $ip
fi
done
You needed the ; then after the if [ ... ] statement (same thing goes for elif, not else), and a space between the last bracket of the statement and the statement's contents. Also this appears to work fine with just single brackets, and this may be more portable (see here).
Works on Bash 4.2.47
Yes. You can use a newline instead of ; if you like, but you always need the then keyword.
if [ "1" == "$(ping -c 1 $ip | grep 'packets transmitted' | cut -d ' ' -f 4)" ]
then echo $ip
fi
# or
if [ "1" == "$(ping -c 1 $ip | grep 'packets transmitted' | cut -d ' ' -f 4)" ]
then
echo $ip
fi

Bash ping status script

I've done the following script
HOSTS="ns1.server.com ns2.server.com"
SUBJECT="Host Down"
for myHost in $HOSTS
do
count=$(ping -c 10 $myHost | grep 'received' | awk -F',' '{ print $2 }' | awk '{
print $1 }')
if [ $count -eq 0 ]; then
echo "Host : $myHost is down (ping failed) at $(date)" | sendEmail -f email (email address removed) -u "$SUBJECT" etc etc
fi
done
Run via cron every 5 minutes however when a host is down I will receive and email every 5 minutes reflecting this. What i'd like is to add the function so that it only emails me when the status has changed. ie if it's down I don't want it to send any further updates until it's up.
I think something like this can help:
#!/bin/bash
HOSTS="ns1.server.com ns2.server.com"
HOSTS="123.123.1.1 ns1.server.com"
SUBJECT="Host Down"
ping_attempts=1
down_hosts=down_hosts.txt
for myHost in $HOSTS
do
count=$(ping -c $ping_attempts $myHost | awk -F, '/received/{print $2*1}')
echo $count
if [ $count -eq 0 ]; then
echo "$myHost is down"
if [ $(grep -c "$myHost" "$down_hosts") -eq 0 ]; then
echo "Host : $myHost is down (ping failed) at $(date)"
echo "$myHost" >> $down_hosts
fi
else
echo "$myHost is alive"
if [ $(grep -c "$myHost" "$down_hosts") -eq 1 ]; then
echo "Host : $myHost is up (ping ok) at $(date)"
sed -i "/$myHost/d" "$down_hosts"
fi
fi
done
There is a good point in the comments that you might want to use an infinite loop. But as you have asked for something different, here you go:
HOSTS="ns1.server.com ns2.server.com"
SUBJECT="Host Down"
PATH_STATUS='/yourfolder/hoststatus_' # For example can be located in /tmp.
for myHost in $HOSTS; do
count=$(ping -c 10 "$myHost" | grep 'received' | awk -F',' '{ print $2 }' | awk '{ print $1 }')
[[ -f "$PATH_STATUS$myHost"]] && prevStatus=$(cat "$PATH_STATUS$myHost") || prevStatus='unknown'
[[ $count == 0 ]] && curStatus='down' || curStatus='up'
if [[ $curStatus != $prevStatus ]]; then
echo "$curStatus" > "$PATH_STATUS$myHost"
echo "Host : $myHost is $curStatus at $(date)" | sendEmail
fi
done

If or while loop inside case command positional parameters

Being relatively new to anything other than bash scripting, I have created a script to
check if a process is running
output PID's to the shell
if not prompt user input and start etc/etc.
I've moved onto positional parameters and can't see where I'm going wrong:
if [ "$1" == "" ]; then
proc_finder
elif [ $1 != "" ];then
case $1 in
-p | --process )
shift
z=$(ps aux |grep $1 |grep -v grep > /dev/null)
if [ ! -z "$z" ]; then
echo "YES"
else
echo "NO"
fi
;;
* )
echo "Usage -p (process)"
esac
fi
This always seems to return yes even when putting in -p test for example. I know im doing something fundamentally wrong, looking at the verbose output the grep -v grep is being done last hence I believe it always returnes an exit state of 0.
Shouldn't that be if [ $? -eq 0 ]?
EDIT 1
You can try this:
z=`ps aux | grep $1 | grep -v grep > /dev/null`
if [ ! -z "$z" ]; then
echo "YES"
else
echo "NO"
fi
If $z is not empty (-z: test for zero-length string) this implies the process was found with the ps command.
EDIT 2
The ps ... grep ... grep is being redirect to /dev/null. That means z will contain nothing. remove the redirection and z should have some output.
z=`ps aux | grep $1 | grep -v grep`
EDIT 3
Alternatively, you can just do this:
ps aux | grep $1 | grep -v grep > /dev/null 2>&1
if [ $? -eq 0 ]; then
echo "YES"
else
echo "NO"
fi
In this case, you are not saving the grep output. That's good if you don't really need it.

bash script and greping with command line

new to bash scripting so just wondering if i am doing this code right at all. im trying to search /etc/passwd and then grep and print users.
usage ()
{
echo "usage: ./file.sk user"
}
# test if we have two arguments on the command line
if [ $# != 1 ]
then
usage
exit
fi
if [[ $# < 0 ]];then
usage
exit
fi
# Search for user
fullname=`grep $1 /etc/passwd | cut -f 5 -d :`
firstname=`grep $1 /etc/passwd | cut -f 5 -d : | cut -f 1 -d " "`
#check if there. if name is founf: print msg and line entry
not sure as how to this or if im doing this right...
am i doing this right?
grep $1 /etc/passwd | while IFS=: read -r username passwd uid gid info home shell
do
echo $username: $info
done
This might work for you:
fullname=$(awk -F: '/'$1'/{print $5}' /etc/passwd)
firstname=${fullname/ *}
You're on the right track.
But I think the 2nd if [[ $# < 0 ]] .... fi block doesn't get you much. Your first test case gets the situation right, 'This script requires 1 argument or quits'.
Also, I don't see what you need firstname for, so a basic test is
case "${fullname:--1}" in
-[1] ) printf "No userID found for input=$1\n" ; exit 1 ;;
* )
# assume it is OK
# do what every you want after this case block
;;
esac
You can of course, duplicate this using "${firstname}" if you really need the check.
OR as an equivalent if ... fi is
if [[ "${fullname}" == "" ]] ; then
printf "No userID found for input=$1\n" ; exit 1
fi
note to be more efficient, you can parse ${fullname} to get firstname without all the calls to grep etc, i.e.
firstname=${fullname%% *}
Let me know if you need for me to explain :--1} and %% *} variable modifiers.
I hope this helps.
Instead of this:
fullname=`grep $1 /etc/passwd | cut -f 5 -d :`
firstname=`grep $1 /etc/passwd | cut -f 5 -d : | cut -f 1 -d " "`
Try this:
fullname=$(cut -f5 -d: /etc/passwd | grep "$1")
if [[ $? -ne 0 ]]; then
# not found, do something
fi
firstname=${fullname%% *} # remove the space and everything after
Note that I changed my answer to cut before grep so that it doesn't get false positives if some other field matches the full name you are searching for.
You can simply by reading your input to an array and then printing out your desired fields, something like this -
grep $1 /etc/passwd | while IFS=: read -a arry; do
echo ${arry[0]}:${arry[4]};
done
Test:
jaypal:~/Temp] echo "root:*:0:0:System Administrator:/var/root:/bin/sh" |
while IFS=: read -a arry; do
echo ${arry[0]}:${arry[4]};
done
root:System Administrator

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