I need a Bash one liner that can print all occupied IPs in a CIDR that I give it, and I did not manage to find how to do it. I have a script that can perform this, but I did not manage to get it to run as a one liner. The script:
#!/bin/sh
pingf(){
if ping -w 2 -q -c 1 10.5.99."$1" > /dev/null ;
then
printf "IP %s is up\n" 10.5.99."$1"
fi
}
main(){
NUM=1
while [ $NUM -lt 255 ];do
pingf "$NUM" &
NUM=$(expr "$NUM" + 1)
done
wait
}
main
Any help will be appreciated!
Use a for loop with a sequence expression.
Replace the if statement with && to combine the ping and printf.
for ip in 10.5.99.{1..255}; do ping -w 2 -q -c 1 "$ip" >/dev/null && printf "IP %s is up\n" "$ip" & done
wait
Sequence expressions are a bash extension, so you'll need to change #!/bin/sh to #!/bin/bash.
Note that this just tests a single /24, not an arbitrary CIDR block. I can't think of a way to generalize this to CIDR blocks in a one-liner.
Related
I have list of IP's which has to be pinged each other. Once I SSH to IP-1, i should ping all IP's in a loop before I come out of the loop.
I have tried the below..
for name in "${ip[#]}";
do
status=$(ssh -n -o LogLevel=QUIET -t -t -o StrictHostKeyChecking=no
ubuntu#$node ping -W 2 -q -c 5 $name")
if [ "$?" -eq "2" ]; then
echo -e "$(tput setab 7) $(tput setaf 1)$(date) $i unable to ping $name
$(tput sgr0)"
fi
done
This code is working. However every time it requires to do SSH, which is having a performance impact as i'm having more than 100 IP's in the list.
Can I get any help on this?
You could just make this list part of the command that you run on your target host, something like this:
ips=( "10.0.0.1" "10.0.0.2")
ssh serverName 'for i in '${ips[#]}'; do ping ${i} -c1; done'
Note the breaking single-quote to pass the array.
Edit:
Just to have it mentioned here: the tool "fping" is quite right for the job. It would give you just the list you asked for:
ips=( "10.0.0.1" "10.0.0.2")
ssh serverName 'fping -a '${ips[#]}' 2>/dev/null'
Cupcake is right about the possible problems that arise when you passing the list as suggested having entries containing whitespaces. In this special case, however, there are no whitespaces to be expected.
This should give you the List of IPs without fping
ips=( "10.0.0.1" "10.0.0.2")
ssh serverName 'for host in '${ips[#]}'; do if ping -c1 -w1 ${host} >/dev/null 2>&1; then echo ${host};fi;done'
Please explain to me why the very last echo statement is blank? I expect that XCODE is incremented in the while loop to a value of 1:
#!/bin/bash
OUTPUT="name1 ip ip status" # normally output of another command with multi line output
if [ -z "$OUTPUT" ]
then
echo "Status WARN: No messages from SMcli"
exit $STATE_WARNING
else
echo "$OUTPUT"|while read NAME IP1 IP2 STATUS
do
if [ "$STATUS" != "Optimal" ]
then
echo "CRIT: $NAME - $STATUS"
echo $((++XCODE))
else
echo "OK: $NAME - $STATUS"
fi
done
fi
echo $XCODE
I've tried using the following statement instead of the ++XCODE method
XCODE=`expr $XCODE + 1`
and it too won't print outside of the while statement. I think I'm missing something about variable scope here, but the ol' man page isn't showing it to me.
Because you're piping into the while loop, a sub-shell is created to run the while loop.
Now this child process has its own copy of the environment and can't pass any
variables back to its parent (as in any unix process).
Therefore you'll need to restructure so that you're not piping into the loop.
Alternatively you could run in a function, for example, and echo the value you
want returned from the sub-process.
http://tldp.org/LDP/abs/html/subshells.html#SUBSHELL
The problem is that processes put together with a pipe are executed in subshells (and therefore have their own environment). Whatever happens within the while does not affect anything outside of the pipe.
Your specific example can be solved by rewriting the pipe to
while ... do ... done <<< "$OUTPUT"
or perhaps
while ... do ... done < <(echo "$OUTPUT")
This should work as well (because echo and while are in same subshell):
#!/bin/bash
cat /tmp/randomFile | (while read line
do
LINE="$LINE $line"
done && echo $LINE )
One more option:
#!/bin/bash
cat /some/file | while read line
do
var="abc"
echo $var | xsel -i -p # redirect stdin to the X primary selection
done
var=$(xsel -o -p) # redirect back to stdout
echo $var
EDIT:
Here, xsel is a requirement (install it).
Alternatively, you can use xclip:
xclip -i -selection clipboard
instead of
xsel -i -p
I got around this when I was making my own little du:
ls -l | sed '/total/d ; s/ */\t/g' | cut -f 5 |
( SUM=0; while read SIZE; do SUM=$(($SUM+$SIZE)); done; echo "$(($SUM/1024/1024/1024))GB" )
The point is that I make a subshell with ( ) containing my SUM variable and the while, but I pipe into the whole ( ) instead of into the while itself, which avoids the gotcha.
#!/bin/bash
OUTPUT="name1 ip ip status"
+export XCODE=0;
if [ -z "$OUTPUT" ]
----
echo "CRIT: $NAME - $STATUS"
- echo $((++XCODE))
+ export XCODE=$(( $XCODE + 1 ))
else
echo $XCODE
see if those changes help
Another option is to output the results into a file from the subshell and then read it in the parent shell. something like
#!/bin/bash
EXPORTFILE=/tmp/exportfile${RANDOM}
cat /tmp/randomFile | while read line
do
LINE="$LINE $line"
echo $LINE > $EXPORTFILE
done
LINE=$(cat $EXPORTFILE)
This is my first bash script using some resources I found online. I think there is a better way to write this perhaps using some other form of conditionals (if then vs control operators).
It is a script that basically checks if a host is up or down (check if it is ping-able). You dump all the ip addresses you want into a file, then run the script calling on the file. The text file looks like this:
8.8.8.8
4.8.8.8
4.4.4.4
127.0.0.1
The actual script looks like this. Is the 2>&1 necessary because it worked without. I had to play around with the brackets a lot.
#!/bin/bash
while read line
do
A=$(ping -c 1 $line)
((echo $A | grep "64 bytes") > /dev/null 2>&1 && (echo "UP - "$line)) || echo "DOWN - "$line
done < $1
Thank you!
You can do it entirely without brackets:
while read -r address; do
ping -c 1 $address >/dev/null 2>&1 && echo "UP - $address" || echo "DOWN - $address"
done < file
The >/dev/null 2>&1 redirects both STDOUT and STDERR to /dev/null meaning that whatever ping outputs won't be printed to your terminal.
You can then use the && and || operators to echo a message in case of success (ping exits with 0) or failure (ping exits with >0)
You could use if..then..else if you prefer:
while read -r address; do
if ping -c 1 $address > /dev/null 2>&1; then
echo "UP - $address"
else
echo "DOWN - $address"
fi
done < file
arco444 has the right answer. Some other notes
with the form A && B || C, if A succeeds then B executes; if B fails, C will execute. That will not occur for if A; then B; else C; fi
proper indentation is extremely helpful to identify errors (none here, but in general)
Use better variable names: $ip is more meaningful than $line
variables go inside the quotes
parentheses introduce subshells, which will reduce performance. Use only when necessary
I'm looking for alternatives to working out the ping between two machine (mA and mB) and report this back to Nagios (on mC).
My current thoughts are to write a BASH script that will ping the machines in a cron job, output the data to a file then have another bash script that Nagios can use to read that file. This doesn't feel like the best/right way to do this though?
Here's the script I plan to run in the cron job:
#!/bin/bash
if [ -z "$1" ] || [ -z "$2" ] || [ -z "$3" ] || [ -z "$4" ]
then
echo $0: usage: $0 file? ip? pingcount? deadline?
exit 126
else
FILE=$1
IP=$2
PCOUNT=$3
DLINE=$4
while read line
do
if [[ $line == rtt* ]]
then
#replace forward slash with underscore
line=${line////_}
#replace spaces with underscore
line=${line// /_}
#get the 8 item when splitting string on underscore
#echo $line| cut -d'_' -f 8 >> $FILE #Append
#echo $line| cut -d'_' -f 8 > $FILE #Overwrite
echo $line| cut -d'_' -f 8
fi
done < <(ping $IP -c $PCOUNT -q -w $DLINE) #-q output summary / -w deadline / -c pint count
I though about using trace route, but I think this would be produces a slower ping?, is there another way to achieve what I want?
Note: I know Nagios can directly ping a machine, but this isn't what I want to do and won't tell me what I want. Also this is my second script ever, so it's probably rubbish. Also, what alternative would I have if ICMP was blocked?
Have you looked at NRPE and check_ping? This would allow the nagios machine (mC) to ask mA to ping mB and then mA would report the results to mC. You would need to install and configure NRPE and the nagios-plugins on mA for this to work.
#!/bin/bash
hello()
{
SRC=$1
DEST=$2
for IP in `cat /opt/ankit/configs/machine.configs` ; do
echo $SRC | grep '*' > /dev/null
if test `echo $?` -eq 0 ; then
for STAR in $SRC ; do
echo -en "$IP"
echo -en "\n\t ARG1=$STAR ARG2=$2\n\n"
done
else
echo -en "$IP"
echo -en "\n\t ARG1=$SRC ARG2=$DEST\n\n"
fi
done
}
hello $1 $2
The above is the shell script which I provide source (SRC) & desitnation (DEST) path. It worked fine when I did not put in a SRC path with wild card ''. When I run this shell script and give ''.pdf or '*'as follows:
root#ankit1:~/as_prac# ./test.sh /home/dev/Examples/*.pdf /ankit_test/as
I get the following output:
192.168.1.6
ARG1=/home/dev/Examples/case_Contact.pdf ARG2=/home/dev/Examples/case_howard_county_library.pdf
The DEST is /ankit_test/as but DEST also get manupulated due to '*'. The expected answer is
ARG1=/home/dev/Examples/case_Contact.pdf ARG2=/ankit_test/as
So, if you understand what I am trying to do, please help me out to solve this BUG.
I'll be grateful to you.
Thanks in advance!!!
I need to know exactly how I use '*.pdf' in my program one by one without disturbing DEST.
Your script needs more work.
Even after escaping the wildcard, you won't get your expected answer. You will get:
ARG1=/home/dev/Examples/*.pdf ARG2=/ankit__test/as
Try the following instead:
for IP in `cat /opt/ankit/configs/machine.configs`
do
for i in $SRC
do
echo -en "$IP"
echo -en "\n\t ARG1=$i ARG2=$DEST\n\n"
done
done
Run it like this:
root#ankit1:~/as_prac# ./test.sh "/home/dev/Examples/*.pdf" /ankit__test/as
The shell will expand wildcards unless you escape them, so for example if you have
$ ls
one.pdf two.pdf three.pdf
and run your script as
./test.sh *.pdf /ankit__test/as
it will be the same as
./test.sh one.pdf two.pdf three.pdf /ankit__test/as
which is not what you expect. Doing
./test.sh \*.pdf /ankit__test/as
should work.
If you can, change the order of the parameters passed to your shell script as follows:
./test.sh /ankit_test/as /home/dev/Examples/*.pdf
That would make your life a lot easier since the variable part moves to the end of the line. Then, the following script will do what you want:
#!/bin/bash
hello()
{
SRC=$1
DEST=$2
for IP in `cat /opt/ankit/configs/machine.configs` ; do
echo -en "$IP"
echo -en "\n\t ARG1=$SRC ARG2=$DEST\n\n"
done
}
arg2=$1
shift
while [[ "$1" != "" ]] ; do
hello $1 $arg2
shift
done
You are also missing a final "done" to close your outer for loop.
OK, this appears to do what you want:
#!/bin/bash
hello() {
SRC=$1
DEST=$2
while read IP ; do
for FILE in $SRC; do
echo -e "$IP"
echo -e "\tARG1=$FILE ARG2=$DEST\n"
done
done < /tmp/machine.configs
}
hello "$1" $2
You still need to escape any wildcard characters when you invoke the script
The double quotes are necessary when you invoke the hello function, otherwise the mere fact of evaluating $1 causes the wildcard to be expanded, but we don't want that to happen until $SRC is assigned in the function
Here's what I came up with:
#!/bin/bash
hello()
{
# DEST will contain the last argument
eval DEST=\$$#
while [ $1 != $DEST ]; do
SRC=$1
for IP in `cat /opt/ankit/configs/machine.configs`; do
echo -en "$IP"
echo -en "\n\t ARG1=$SRC ARG2=$DEST\n\n"
done
shift || break
done
}
hello $*
Instead of passing only two parameters to the hello() function, we'll pass in all the arguments that the script got.
Inside the hello() function, we first assign the final argument to the DEST var. Then we loop through all of the arguments, assigning each one to SRC, and run whatever commands we want using the SRC and DEST arguments. Note that you may want to put quotation marks around $SRC and $DEST in case they contain spaces. We stop looping when SRC is the same as DEST because that means we've hit the final argument (the destination).
For multiple input files using a wildcard such as *.txt, I found this to work perfectly, no escaping required. It should work just like a native bash app like "ls" or "rm." This was not documented just about anywhere so since I spent a better part of 3 days trying to figure it out I decided I should post it for future readers.
Directory contains the following files (output of ls)
file1.txt file2.txt file3.txt
Run script like
$ ./script.sh *.txt
Or even like
$ ./script.sh file{1..3}.txt
The script
#!/bin/bash
# store default IFS, we need to temporarily change this
sfi=$IFS
#set IFS to $'\n\' - new line
IFS=$'\n'
if [[ -z $# ]]
then
echo "Error: Missing required argument"
echo
exit 1
fi
# Put the file glob into an array
file=("$#")
# Now loop through them
for (( i=0 ; i < ${#file[*]} ; i++ ));
do
if [ -w ${file[$i]} ]; then
echo ${file[$i]} " writable"
else
echo ${file[$i]} " NOT writable"
fi
done
# Reset IFS to its default value
IFS=$sfi
The output
file1.txt writable
file2.txt writable
file3.txt writable
The key was switching the IFS (Internal Field Separator) temporarily. You have to be sure to store this before switching and then switch it back when you are done with it as demonstrated above.
Now you have a list of expanded files (with spaces escaped) in the file[] array which you can then loop through. I like this solution the best, easiest to program for and easiest for the users.
There's no need to spawn a shell to look at the $? variable, you can evaluate it directly.
It should just be:
if [ $? -eq 0 ]; then
You're running
./test.sh /home/dev/Examples/*.pdf /ankit_test/as
and your interactive shell is expanding the wildcard before the script gets it. You just need to quote the first argument when you launch it, as in
./test.sh "/home/dev/Examples/*.pdf" /ankit_test/as
and then, in your script, quote "$SRC" anywhere where you literally want the things with wildcards (ie, when you do echo $SRC, instead use echo "$SRC") and leave it unquoted when you want the wildcards expanded. Basically, always put quotes around things which might contain shell metacharacters unless you want the metacharacters interpreted. :)