I am trying to write a bash script where i will give an IP as an argument. If the IP is not valid I want to print to screen a message.If the IP is valid I print the hostname.
host $1 | cut -d' ' -f5
This is my code if the IP is valid. I don't know hot to compare the output if it's not valid to print the corresponding message
You can do it this way:
if host=$(host "$1" 2>/dev/null); then # ignore stderr
echo "$host"
else
echo "$1 is not a valid host"
fi
If you want to display the error output of host in the else part, then:
if host=$(host "$1" 2>&1); then # merge stdout and stderr
echo "$host"
else
echo "$1 is not a valid host, error=$host"
fi
Related
First time post, please forgive any missing information.
I have a script that is supposed to work with icinga. I need icinga to log into my Linux box and run a command like "script ". The script will then run a command to that hostname like sudo /etc/init.d/apache2 status then report back "running or unused" and an exit status of 0 or 2.
I'm wondering how I could add another command and have it one or the other run depending on what hostname it's given. Half of them need apache2 to be running and the other half need to have a process called dss to be running. I'd rather not have two separate scripts. Here is the working script and sorry it's sloppy but I haven't done any clean up and I'm not real good at bash yet.
so the user would run the script ./chkdss2 or
#!/bin/bash
ec=0
ec1=2
var3=run
var4=unused
for host in "$#"
do
var1=`ssh $host sudo /etc/init.d/dss status|awk '{print $6}'`
var2="$( echo $var1 | cut -c 3-5 )"
if [[ "$var2" == "$var3" ]]; then
echo "$host is running"
echo $ec
else
echo "$host is not running"
echo $ec1
fi
done
There are a couple ways to test if a particular hostname is for apache or dss. You only need to have a list of hostnames for each case, and check if the received hostnames are included in said lists.
Method 1: using arrays
#!/bin/bash
# Method 1, using array lists of hosts
apachehosts=('ap1' 'ap2' 'ap3')
dsshosts=('dss1' 'dss2' 'dss3')
for host in "$#"
do
if printf '%s\n' "${apachehosts[#]}" | grep -Fxq "$host"
then
echo "$host: APACHE HOST"
elif printf '%s\n' "${dsshosts[#]}" | grep -Fxq "$host"
then
echo "$host: DSS HOST"
else
echo "ERROR, $host: unknown host"
fi
done
To modify the lists of hosts, simply add or remove values in the declaration of arrays apachehosts and dsshosts.
Method 2: using case
#!/bin/bash
# Method 2, using case
for host in "$#"
do
case "$host" in
'ap1'|'ap2'|'ap3')
echo "CASE, $host: APACHE HOST"
;;
'dss1'|'dss2'|'dss3')
echo "CASE, $host: DSS HOST"
;;
*)
echo "ERROR CASE, $host: unknown host"
;;
esac
done
Here, you edit the patterns in each case.
Method 3: using if
#!/bin/bash
# Method 3, using if
for host in "$#"
do
if [[ "$host" == 'ap1' || "$host" == 'ap2' || "$host" == 'ap3' ]]
then
echo "IF, $host: APACHE HOST"
elif [[ "$host" == 'dss1' || "$host" == 'dss2' || "$host" == 'dss3' ]]
then
echo "IF, $host: DSS HOST"
else
echo "IF, $host: unknown host"
fi
done
Here you modify the if conditions. I prefer the other methods, since this one is more complicated to edit, it is not as clear, especially if your list of hosts is long.
Method 4: condition on the hostnames
If you are lucky, there is some pattern to your hostnames. Ex. all apache servers start with letters ap, all your dss servers include dss in the name, ...
You can then simply use 2 if statements to decide which is which.
#!/bin/bash
# Method 4, patterns
for host in "$#"
do
if [[ $(echo "$host" | grep -c -e "^ap") -ne 0 ]]
then
echo "PATTERNS, $host: APACHE HOST"
elif [[ $(echo "$host" | grep -c -e "dss") -ne 0 ]]
then
echo "PATTERNS, $host: DSS host"
else
echo "PATTERNS, $host: unknown host"
fi
done
Note: hostname apdss1 would come out as an Apache server here. Previous methods would respond "unknown host". You patterns must be strict enough to avoid mismatches.
I had a similar task to get few report items using single ssh request.
I had to retrieve in singel ssh command:
Full hostname (FQDN)
Linux version
IP address of its Docker host if exist, or "none"
I got my script to work in 3 stage.
1. Get multiple lines of information from remote host
ssh -q dudi-HP-Compaq-Elite-8300-MT <<< '
date +%F:%T # line 1: time stamp
hostname -f # line 2: hostname
awk "/DESCR/{print \$3}" /etc/lsb-release # line 3 : host linux distribution version
ip a | awk "/inet / && !/127.0.0.1/{sub(\"/.*\",\"\",\$2);printf(\"%s \", \$2)}" # line 4: list IP address to the host
'
Results:
2022-03-05:22:22:21
dudi-HP-Compaq-Elite-8300-MT
20
192.168.2.111 192.168.122.1 172.17.0.1
2. Process multiple lines of information from remote host
Read lines of information from remote host, into an array sshResultsArr.
readarray -t sshResultsArr < <(ssh -q dudi-HP-Compaq-Elite-8300-MT <<< '
date +%F:%T # line 1: time stamp
hostname -f # line 2: hostname
awk "/DESCR/{print \$3}" /etc/lsb-release # line 3 : host linux distribution version
ip a | awk "/inet / && !/127.0.0.1/{sub(\"/.*\",\"\",\$2);printf(\"%s \", \$2)}" # line 4: list IP address to the host
')
hostname=${sshResultsArr[1]}
osVersion=${sshResultsArr[2]}
hasDockerIp=$(grep -Eo "172(.[[:digit:]]{1,3}){3}" <<< "${sshResultsArr[3]}") # find IP starting with 172
hasDockerIp=${hasDockerIp:="none"} # if not found IP set to "NONE"
printf "%s \t OS version: %s \t has Docker IP: %s\n" "$hostname" "$osVersion" "$hasDockerIp"
Result:
dudi-HP-Compaq-Elite-8300-MT OS version: 20 has Docker IP: 172.17.0.1
3. Process each remote host in a loop
#!/bin/bash
for host in "$#"; do
readarray -t sshResultsArr < <(ssh -q $host <<< '
date +%F:%T # line 1: time stamp
hostname -f # line 2: hostname
awk "/DESCR/{print \$3}" /etc/lsb-release # line 3 : host linux distribution version
ip a | awk "/inet / && !/127.0.0.1/{sub(\"/.*\",\"\",\$2);printf(\"%s \", \$2)}" # line 4: list IP address to the host
')
hostname=${sshResultsArr[1]}
osVersion=${sshResultsArr[2]}
hasDockerIp=$(grep -Eo "172(.[[:digit:]]{1,3}){3}" <<< "${sshResultsArr[3]}") # find IP starting with 172
hasDockerIp=${hasDockerIp:="none"} # if not found IP set to "NONE"
printf "%s \t OS version: %s \t has Docker IP: %s\n" "$hostname" "$osVersion" "$hasDockerIp"
done
I was able to take a little bit from the answers I received and put together something that works well. Thank you all for your answers.
for host in "$#"
do
case "$host" in
('vho1uc1-primary'|'vho1uc2-backup'|'vho2uc1-primary'|'vho2uc2-backup'|'vho3uc1-primary'|'vho3uc2-backup'|'vho10uc1-primary')
var1=`ssh "$host" sudo /etc/init.d/apache2 status|awk '{print $4}'`
var2="$( echo $var1 | cut -c 3-5 )"
if [[ "$var2" == "$var3" ]]; then
echo "Apache2 on $host is running"
echo "0"
else
echo "Apache2 on $host is not running"
echo "2"
fi
;;
*)
esac
done
The main issue I am having with this is pinging the read in IP address. It always says that the address is down.
Ping_Sweep()
{
echo -e '\n'
echo '----- Ping Sweep -----'
echo -e '\n'
command date >> pingresults.tx
echo "Enter in the first three number sequences of an IP address (ex. ###.###.###): "
read -r ip_address
for x in $ip_address
do
echo "IP address being pinged: $ip_address"
if ping –c 1 "$x" &> /dev/null
then
echo "IP: $x is up."
else
echo "Ping failed. $x is down."
fi
done
Main_Menu
}
ping –c should be ping -c. Your original command has an en dash. This is usually caused by copying code rendered by a bad blog framework.
I am currently writing the following script that logs into a remote server and runs couple of commands to verify the performance of the server and prints a message based on the output of those commands .But the ssh doesn't work and returns the stats of the server that hosts the script instead .
Script
#!/bin/bash
#######################
#Function to add hosts to the array
#the following function takes the ip addresses provided while the script is run and stores them in an array
#######################
Host_storing_func () {
HOST_array=()
for i in $# ;do
HOST_array+=(${i});
done
#echo ${HOST_array[*]}
}
#######################
#Calling above function
#######################
Host_storing_func "$#"
############################################################
#Collect Stats of Ping,memory,iowait time test function
############################################################
b=`expr ${#HOST_array[*]} - 1 `
for i in `seq 0 $b` ;do
sshpass -f /root/scripts/passwordFile.txt /usr/bin/ssh student35#${HOST_array[${i}]} << HERE
echo `hostname`
iowaittm=`sar 2 2|awk '/^Average/{print $5};'`
if [ $iowaittm > 10 ];then
echo "IO ==> BAD"
else
echo "IO ==> GOOD"
fi
memoryy=`free -m |grep Swap|awk '{if($2 == 0) print 0;else print (($4 / $2 ) * 100)}'`
if [ ${memoryy} < '10' ] ;then
echo "memory ==> good"
elif [[ "${memory}" -ge 0 ]] && [[ "${memory}" -le 10 ]];then
echo "No Swap"
else
echo "memory ==> bad"`enter code here`
fi
ping -w2 -c2 `hostname` | grep "packet loss"|awk -F, '{print $3}'|awk -F% '{print $1}'|sed 's/^ *//'|awk '{if ($1 == 0) print "Yes" ;else print "No"}'
HERE
done
Output : oc5610517603.XXX.com is the name of the source server
[root#oc5610517603 scripts]# ./big_exercise.sh 9.XXX.XXX.XXX 9.XXX.XXX.XXX
Pseudo-terminal will not be allocated because stdin is not a terminal.
oc5610517603.XXX.com
IO ==> GOOD
No Swap
ping: oc5610517603.ibm.com: Name or service not known
Pseudo-terminal will not be allocated because stdin is not a terminal.
oc5610517603.XXX.com
IO ==> GOOD
No Swap
ping: oc5610517603.XXX.com: Name or service not known
thanks for checking the script , I figured out a way to solve the problem
It is the sshpass command that is causing issue , you just have to put the opening HERE in single quotes if you want to use variables with in the HEREdoc but if the variables are calculated before ssh then you don't have to put opening HERE in single quotes
sshpass -f /root/scripts/passwordFile.txt /usr/bin/ssh -T student35#${i} << 'HERE'
after I changed the sshpass command as above my script worked
I have modified your script a bit.
As suggested by #chepner, I am not using the Host_storing_func.
Heredocs for sshpaas are somewhat tricky. You have to escape every back-tick and $ sign in the heredoc.
Notice the - before the heredoc start, it allows you to indent the heredoc body. Also, try to avoid back-ticks when you can. use $(command) instead.
Hope it helps.
#!/bin/bash
#######################
#Function to add hosts to the array
#the following function takes the ip addresses provided while the script is run and stores them in an array
#######################
array=( "$#" )
user="student35"
############################################################
#Collect Stats of Ping,memory,iowait time test function
############################################################
for host in ${array[#]}; do
sshpass -f /root/scripts/passwordFile.txt /usr/bin/ssh -l ${user} ${host} <<-HERE
thishost=\$(hostname)
echo "Current Host -> \$thishost";
iowaittm=\`sar 2 2|awk '/^Average/{print \$5}'\`
if [ \$iowaittm > 10 ]; then
echo "IO ==> BAD"
else
echo "IO ==> GOOD"
fi
memory=\$(free -m | grep Swap | awk '{if(\$2 == 0) print 0;else print ((\$4 / \$2 ) * 100)}')
if [ \${memory} < '10' ] ;then
echo "memory ==> good"
elif [[ "\${memory}" -ge 0 ]] && [[ "\${memory}" -le 10 ]]; then
echo "No Swap"
else
echo "memory ==> bad"\`enter code here\`
fi
ping -w2 -c2 \`hostname\` | grep "packet loss"|awk -F, '{print \$3}'|awk -F% '{print \$1}'|sed 's/^ *//'|awk '{if (\$1 == 0) print "Yes" ;else print "No"}'
HERE
done
I want to use fping to ping multiple ips contained in a file and output the failed ips into a file i.e.
hosts.txt
8.8.8.8
8.8.4.4
1.1.1.1
ping.sh
#!/bin/bash
HOSTS="/tmp/hosts.txt"
fping -q -c 2 < $HOSTS
if ip down
echo ip > /tmp/down.log
fi
So I would like to end up with 1.1.1.1 in the down.log file
It seems that parsing the data from fping is somewhat difficult. It allows the parsing of data for hosts that is alive but not dead. As a way round the issue and to allow for multiple host processing simultaneously with -f, all the hosts that are alive are placed in a variable called alive and then the hosts in the /tmp/hosts.txt file are looped through and grepped against the variable alive to decipher whether the host is alive or dead. A return code of 1 signifies that grep cannot find the host in alive and hence an addition to down.log.
alive=$(fping -c 1 -f ipsfile | awk -F: '{ print $1 }')
while read line
do
grep -q -o $line <<<$alive
if [[ "$?" == "1" ]]
then
echo $line >> down.log
fi
done < /tmp/hosts.txt
Here's one way to get the result you want. Note however; i didn't use fping anywhere in my script. If the usage of fping is crucial to you then i might have missed the point entirely.
#!/bin/bash
HOSTS="/tmp/hosts.txt"
declare -i DELAY=$1 # Amount of time in seconds to wait for a packet
declare -i REPEAT=$2 # Amount of times to retry pinging upon failure
# Read HOSTS line by line
while read -r line; do
c=0
while [[ $c < $REPEAT ]]; do
# If pinging an address does not return the word "0 received", we assume the ping has succeeded
if [[ -z $(ping -q -c $REPEAT -W $DELAY $line | grep "0 received") ]]; then
echo "Attempt[$(( c + 1))] $line : Success"
break;
fi
echo "Attempt[$(( c + 1))] $line : Failed"
(( c++ ))
done
# If we failed the pinging of an address equal to the REPEAT count, we assume address is down
if [[ $c == $REPEAT ]]; then
echo "$line : Failed" >> /tmp/down.log # Log the failed address
fi
done < $HOSTS
Usage: ./script [delay] [repeatCount] -- 'delay' is the total amount of seconds we wait for a response from a ping, 'repeatCount' is how many times we retry pinging upon failure before deciding the address is down.
Here we are reading the /tmp/hosts.txt line by line and evaluating each adress using ping. If pinging an address succeeds, we move on to the next one. If an address fails, we try again for as many times as the user has specified. If the address fails all of the pings, we log it in our /tmp/down.log.
The conditions for checking whether a ping failed/succeeded may not be accurate for your use-cases, so maybe you will have to edit that. Still, i hope this gets the general idea across.
I am working on a script to read from a file having multiple IP addresses, login to each system (no ssh keys involved and manually entering password), execute a command depending on OS type and print the result.
Here is how IPs are defined in the hosts.txt file
#~] cat hosts.txt
10.6.3.131
10.6.3.132
10.6.3.11
10.6.3.12
When I execute the below script, the following errors are shown. Also, The script does not prompt for 2nd and rest IPs in the list. What could be causing this?
# ./hq-test1.sh
root#10.6.3.131's password:
awk: cmd. line:1: NR==1{print
awk: cmd. line:1: ^ unexpected newline or end of string
bash: line 2: [: !=: unary operator expected
10.6.3.131 == PASS
This is the script used in test :
#!/bin/bash
while read HOST; do
if ssh root#$HOST '
STATUS=`awk 'NR==1{print $1}' /etc/*release`
[ $STATUS != "CentOS" ]
'; then
echo "$HOST == FAIL"
else
echo "$HOST == PASS"
fi
done < hosts.txt
Your script isn't closing stdin while running the ssh command so only the first host of the list is processed.
I also simplified the test, as awk is able to check the OS name and the temporary variable is unnecessary.
while read host; do
if ssh -n root#$host '[ "$(awk "/CentOS/{print}" /etc/*release)" ] '
then
echo "$host == PASS"
else
echo "$host == FAIL"
fi
done < hosts.txt
This worked for me. As I already wrote, it's just a quoting issue.
#!/bin/bash
echo localhost | while read HOST; do
if ssh root#$HOST '
STATUS=`awk "NR==1{print \$1}" /etc/*release`
[ $STATUS != "CentOS" ]
'; then
echo "$HOST == FAIL"
else
echo "$HOST == PASS"
fi
done