I have an error in the ifplugd.
Whenever a new ethernet cable is plugged into my appliance, then ifplugd should ping the Gateway.
This is what the script looks like:
ping.sh
#!/bin/bash
echo "in ifplugd" >> /tmp/ifplugd.txt
if [ "$2" == "up" ]; then
logger IfPlugD executes script
echo "Pinging 10.10.10.1 5 times"
echo "Executing State $2 ifdown ifup on :: $1 :: $(date)" >> /var/ifplugdlog.txt
ping 10.10.10.1 -c 5;
fi
Sadly, it $2 variable returns nothing.
I tried to check, why it returns nothing, so I ran the ifplugd.action script, which is runs automatically everytime a state changes. It looks like the following:
ifplugd.action
#!/bin/sh
set -e
case "$2" in
up)
run-parts --arg="$1" --arg="$2" /etc/ifplugd/action.d/
;;
down)
run-parts --reverse --arg="$1" --arg="$2" /etc/ifplugd/action.d/
*)
echo "ifplugd.action: Incorrect action argument" >&2
exit 1
;;
esac
It runs with the following arguments in the /etc/default/ifplugd-file
ifplugd
INTERFACES="enp2s0 enp3s0 enp6s0"
HOTPLUG_INTERFACES="enp2s0 enp3s0 enp6s0"
ARGS="-q -f -d10 -w -I"
SUSPEND_ACTION="stop"
And when I remove the network cable and attach it again, it still gives me no response, since my the if clause is getting ignored in my ping.sh, because the $2 variable is null.
Can someone help me, why I get the error "ifplugd: Incorrect action arguments" and how to fix it?
Thanks a lot.
Package seems to be out of date - used another package and made a cron
To check if mdnsd is in probing mode we are using below command to browse for service and redirect its output a file, and hostname of the device is found in the command we decide that mdnsd is in probing mode.
command used for publishing service
dns-sd -R "Test status" "_mytest._tcp." "local." "22"
To browse the service following command is used (Running in background)
dns-sd -lo -Z _mytest._tcp > /tmp/myfile &
To display the content of the file used cat.
cat /tmp/myfile
myfile is empty, if > replaced with tee , I see output on console myfile remains empty.
I am unable to understand what is going on.
Is there any pointer, help
EDIT
Just for completeness adding output, which i missed adding before.
# dns-sd -lo -Z _mytest._tcp local
Using LocalOnly
Using interface -1
Browsing for _mytest._tcp
DATE: ---Tue 25 Apr 2017---
11:09:24.775 ...STARTING...
; To direct clients to browse a different domain, substitute that domain in place of '#'
lb._dns-sd._udp PTR #
; In the list of services below, the SRV records will typically reference dot-local Multicast DNS names.
; When transferring this zone file data to your unicast DNS server, you'll need to replace those dot-local
; names with the correct fully-qualified (unicast) domain name of the target host offering the service.
_mytest._tcp PTR Test\032status._mytest._tcp
Test\032status._mytest._tcp SRV 0 0 22 DevBoard.local. ; Replace with unicast FQDN of target host
Test\032status._mytest._tcp TXT ""
You appear to have a program with behavior that differs based on whether its output is to a TTY. One workaround is to use a tool such as unbuffer or script to simulate a TTY.
Moreover, inasmuch as the use of a file at all is done as a workaround, I suggest using a FIFO to actually capture the line you want without needing to write to a file and poll that file's contents.
#!/bin/sh
newline='
'
# Let's define some helpers...
cleanup() {
[ -e /proc/self/fd/3 ] && exec 3<&- ## close FD 3 if it's open
rm -f "fifo.$$" ## delete the FIFO from disk
if [ -n "$pid" ] && kill -0 "$pid" 2>/dev/null; then ## if our pid is still running...
kill "$pid" ## ...then shut it down.
fi
}
die() { cleanup; echo "$*" >&2; exit 1; }
# Create a FIFO, and start `dns-sd` in the background *thinking* it's writing to a TTY
# but actually writing to that FIFO
mkfifo "fifo.$$"
script -q -f -c 'dns-sd -lo -Z _mytest._tcp local' /proc/self/fd/1 |
tr -d '\r' >"fifo.$$" & pid=$!
exec 3<"fifo.$$"
while read -t 1 -r line <&3; do
case $line in
"Script started on"*|";"*|"") continue;;
"Using "*|DATE:*|[[:digit:]]*) continue;;
*) result="${result}${line}${newline}"; break
esac
done
if [ -z "$result" ]; then
die "Timeout before receiving a non-boilerplate line"
fi
printf '%s\n' "Retrieved a result:" "$result"
cleanup
I wrote the following script for Linux in order to detect drops in my network connection:
#!/bin/bash
echo "### RUNNING ###"
echo "### $(date) ###"
while true;do
now=$(date +"%T")
if [[ "$(ping -c 1 8.8.8.8 | grep '100.0% packet loss' )" != "" ]]; then
echo "!!! KO ($now)" >> "log_connectivity_$(date +"%F")"
else
echo "OK ($now)" >> "log_connectivity_$(date +"%F")"
fi
sleep 5s
done
What it does is, within a loop, to ping 8.8.8.8 once and, if packet is lost it prints KO and the time and, otherwise, it prints OK and the time.
I would like to translate this bash script into a Windows script, but I have no idea. I would be very grateful if you could help me with this.
Thanks in advance ;)
I am new to bash scripting and trying to figure out why the below script is outputting that Apache server is not running whereas it is running properly.
ps cax | grep httpd
if [ $? -eq 0 ]; then
echo "Process is running."
else
echo "Process is not running."
fi
I'm running it on Ubuntu 14.04.2 LTS
Also, how do I make changes to the script that this can test apache server installed on another machine.
Kindly help
This is a working sample of bash script which check the apache status, restart it automatically if down, and alert by telegram bot within unicode emoji.
#!/bin/bash
telegram=(xxxxx, yyyyyy)
if ! pidof apache2 > /dev/null
then
# web server down, restart the server
echo "Server down"
/etc/init.d/apache2 restart > /dev/null
sleep 10
#checking if apache restarted or not
if pidof apache2 > /dev/null
then
for i in "${telegram[#]}"
do
curl -s -X POST https://api.telegram.org/botxxxxxx:yyyyyyyyyyyyyyyyyyyyyyyyyy/sendMessage -d chat_id="$i" -d text="`echo -e '\U0001F525'` Apache stoped on Molib Stage. Automatically restarted succesfully."
done
else
for i in "${telegram[#]}"
do
curl -s -X POST https://api.telegram.org/botxxxxxx:yyyyyyyyyyyyyyyyyyyyyyyyyy/sendMessage -d chat_id="$i" -d text="`echo -e '\U0001F525'` Apache stoped on Molib Stage. Automatically restart failed. Please check manually."
done
fi
fi
Use this:
service apache2 status
Or this:
service --status-all | grep apache2
Instead of httpd try to grep "apache2". To be sure try to check services with the next command and decide the registered name of the apache webserver:
service --status-all
Try and see - simply simplest, most didactic here and well working on Ubuntu 20.04:
catching output of status to bash variable
"if" status includes substring (from "Active:" statement) - do job you wanted
"else" - do another job you defined
#!/bin/bash
servstat=$(service apache2 status)
if [[ $servstat == *"active (running)"* ]]; then
echo "process is running"
else echo "process is not running"
fi
This work perfect in an old Debian. Remember to run with bash and not with sh.
In Centos replace with httpd.
#!/bin/bash
if [ $(/etc/init.d/apache2 status | grep -v grep | grep 'apache2 is running' | wc -l) > 0 ]
then
echo "Process is running."
else
echo "Process is not running."
fi
## Plz run this script .. its working
------------------------------------------------
ps cax | grep httpd
if [ $? -eq 1 ]
then
echo "Process is running."
else if [ $? -eq 0 ]
echo "Process is not running."
fi
fi
----------------------------------------------
This is menu driven one stop shell script in which you can check the firewall,apache or any other webservices ,you can start or stop the services just by choosing the option in below script
echo "welcome please select your options"
read choice
firewall=`sudo systemctl status firewalld`
apache=`sudo systemctl status apache2`
firewall1=`sudo systemctl stop firewalld`
apache1=`sudo systemctl stop apache2`
startrfirewall=`sudo systemctl start firewalld`
startapache=`sudo systemctl start apache2`
case $choice in
1) status of the firewall is $firewall
;;
2) status of apache is $apache
;;
3) echo stop firewall by $firewall1
;;
4) echo stop apache by $apache1
;;
5) echo start firewall by $startrfirewall
;;
6) echo start apache by $startapache
;;
*) echo exit
esac
I put this together based on the above and made so can use other services.
Hope this helps.
#!/bin/bash
# Must be running as root or via sudo permissions to be able to restart
# Put your process name restart command line in
PROCESS_NAME=httpd
if ! pidof $PROCESS_NAME > /dev/null
then
# web server down, restart the server
echo "Server $PROCESS_NAME down"
/usr/sbin/apachectl restart > /dev/null
echo "Tried restart of $PROCESS_NAME. Waiting 10 seconds to settle."
# wait ten
sleep 10
#checking if process restarted or not
if pidof $PROCESS_NAME > /dev/null
then
echo "$PROCESS_NAME was down but is now up."
else
echo "$PROCESS_NAME is still down. Please take some action."
fi
else
echo "Server $PROCESS_NAME up."
fi
How can an internet connection be tested without pinging some website?
I mean, what if there is a connection but the site is down? Is there a check for a connection with the world?
Without ping
#!/bin/bash
wget -q --spider http://google.com
if [ $? -eq 0 ]; then
echo "Online"
else
echo "Offline"
fi
-q : Silence mode
--spider : don't get, just check page availability
$? : shell return code
0 : shell "All OK" code
Without wget
#!/bin/bash
echo -e "GET http://google.com HTTP/1.0\n\n" | nc google.com 80 > /dev/null 2>&1
if [ $? -eq 0 ]; then
echo "Online"
else
echo "Offline"
fi
Ping your default gateway:
#!/bin/bash
ping -q -w 1 -c 1 `ip r | grep default | cut -d ' ' -f 3` > /dev/null && echo ok || echo error
Super Thanks to user somedrew for their post here: https://bbs.archlinux.org/viewtopic.php?id=55485 on 2008-09-20 02:09:48
Looking in /sys/class/net should be one way
Here's my script to test for a network connection other than the loop back.
I use the below in another script that I have for periodically testing if my website is accessible. If it's NOT accessible a popup window alerts me to a problem.
The script below prevents me from receiving popup messages every five minutes whenever my laptop is not connected to the network.
#!/usr/bin/bash
# Test for network conection
for interface in $(ls /sys/class/net/ | grep -v lo);
do
if [[ $(cat /sys/class/net/$interface/carrier) = 1 ]]; then OnLine=1; fi
done
if ! [ $OnLine ]; then echo "Not Online" > /dev/stderr; exit; fi
Note for those new to bash: The final 'if' statement tests if NOT [!] online and exits if this is the case. See man bash and search for "Expressions may be combined" for more details.
P.S. I feel ping is not the best thing to use here because it aims to test a connection to a particular host NOT test if there is a connection to a network of any sort.
P.P.S. The Above works on Ubuntu 12.04 The /sys may not exist on some other distros. See below:
Modern Linux distributions include a /sys directory as a virtual filesystem (sysfs, comparable to /proc, which is a procfs), which stores and allows modification of the devices connected to the system, whereas many traditional UNIX and Unix-like operating systems use /sys as a symbolic link to the kernel source tree.[citation needed]
From Wikipedia https://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
This works on both MacOSX and Linux:
#!/bin/bash
ping -q -c1 google.com &>/dev/null && echo online || echo offline
In Bash, using it's network wrapper through /dev/{udp,tcp}/host/port:
if : >/dev/tcp/8.8.8.8/53; then
echo 'Internet available.'
else
echo 'Offline.'
fi
(: is the Bash no-op, because you just want to test the connection, but not processing.)
The top answer misses the fact that you can have a perfectly stable connection to your default gateway but that does not automatically mean you can actually reach something on the internet. The OP asks how he/she can test a connection with the world. So I suggest to alter the top answer by changing the gateway IP to a known IP (x.y.z.w) that is outside your LAN.
So the answer would become:
ping -q -w 1 -c 1 x.y.z.w > /dev/null && echo ok || echo error
Also removing the unfavored backticks for command substitution[1].
If you just want to make sure you are connected to the world before executing some code you can also use:
if ping -q -w 1 -c 1 x.y.z.w > /dev/null; then
# more code
fi
I've written scripts before that simply use telnet to connect to port 80, then transmit the text:
HTTP/1.0 GET /index.html
followed by two CR/LF sequences.
Provided you get back some form of HTTP response, you can generally assume the site is functioning.
make sure your network allow TCP traffic in and out, then you could get back your public facing IP with the following command
curl ifconfig.co
Execute the following command to check whether a web site is up, and what status message the web server is showing:
curl -Is http://www.google.com | head -1 HTTP/1.1 200 OK
Status code ‘200 OK’ means that the request has succeeded and a website is reachable.
The top voted answer does not work for MacOS so for those on a mac, I've successfully tested this:
GATEWAY=`route -n get default | grep gateway`
if [ -z "$GATEWAY" ]
then
echo error
else
ping -q -t 1 -c 1 `echo $GATEWAY | cut -d ':' -f 2` > /dev/null && echo ok || echo error
fi
tested on MacOS High Sierra 10.12.6
If your local nameserver is down,
ping 4.2.2.1
is an easy-to-remember always-up IP (it's actually a nameserver, even).
This bash script continuously check for Internet and make a beep sound when the Internet is available.
#!/bin/bash
play -n synth 0.3 sine 800 vol 0.75
while :
do
pingtime=$(ping -w 1 8.8.8.8 | grep ttl)
if [ "$pingtime" = "" ]
then
pingtimetwo=$(ping -w 1 www.google.com | grep ttl)
if [ "$pingtimetwo" = "" ]
then
clear ; echo 'Offline'
else
clear ; echo 'Online' ; play -n synth 0.3 sine 800 vol 0.75
fi
else
clear ; echo 'Online' ; play -n synth 0.3 sine 800 vol 0.75
fi
sleep 1
done
Similarly to #Jesse's answer, this option might be much faster than any solution using ping and perhaps slightly more efficient than #Jesse's answer.
find /sys/class/net/ -maxdepth 1 -mindepth 1 ! -name "*lo*" -exec sh -c 'cat "$0"/carrier 2>&1' {} \; | grep -q '1'
Explenation:
This command uses find with -exec to run command on all files not named *lo* in /sys/class/net/. These should be links to directories containing information about the available network interfaces on your machine.
The command being ran is an sh command that checks the contents of the file carrier in those directories. The value of $interface/carrier has 3 meanings - Quoting:
It seems there are three states:
./carrier not readable (for instance when the interface is disabled in Network Manager).
./carrier contain "1" (when the interface is activated and it is connected to a WiFi network)
./carrier contain "0" (when the interface is activated and it is not connected to a WiFi network)
The first option is not taken care of in #Jesse's answer. The sh command striped out is:
# Note: $0 == $interface
cat "$0"/carrier 2>&1
cat is being used to check the contents of carrier and redirect all output to standard output even when it fails because the file is not readable.
If grep -q finds "1" among those files it means there is at least 1 interface connected. The exit code of grep -q will be the final exit code.
Usage
For example, using this command's exit status, you can use it start a gnubiff in your ~/.xprofile only if you have an internet connection.
online() {
find /sys/class/net/ -maxdepth 1 -mindepth 1 ! -name "*lo*" -exec sh -c 'cat "$0"/carrier 2>&1 > /dev/null | grep -q "1" && exit 0' {} \;
}
online && gnubiff --systemtray --noconfigure &
Reference
Help testing special file in /sys/class/net/
find -exec a shell function?
shortest way: fping 4.2.2.1 => "4.2.2.1 is alive"
i prefer this as it's faster and less verbose output than ping, downside is you will have to install it.
you can use any public dns rather than a specific website.
fping -q google.com && echo "do something because you're connected!"
-q returns an exit code, so i'm just showing an example of running something you're online.
to install on mac: brew install fping; on ubuntu: sudo apt-get install fping
Ping was designed to do exactly what you're looking to do. However, if the site blocks ICMP echo, then you can always do the telnet to port 80 of some site, wget, or curl.
Checking Google's index page is another way to do it:
#!/bin/bash
WGET="/usr/bin/wget"
$WGET -q --tries=20 --timeout=10 http://www.google.com -O /tmp/google.idx &> /dev/null
if [ ! -s /tmp/google.idx ]
then
echo "Not Connected..!"
else
echo "Connected..!"
fi
For the fastest result, ping a DNS server:
ping -c1 "8.8.8.8" &>"/dev/null"
if [[ "${?}" -ne 0 ]]; then
echo "offline"
elif [[ "${#args[#]}" -eq 0 ]]; then
echo "online"
fi
Available as a standalone command: linkStatus
Pong doesn't mean web service on the server is running; it merely means that server is replying to ICMP echo.
I would recommend using curl and check its return value.
If your goal is to actually check for Internet access, many of the existing answers to this question are flawed. A few things you should be aware of:
It's possible for your computer to be connected to a network without that network having internet access
It's possible for a server to be down without the entire internet being inaccessible
It's possible for a captive portal to return an HTTP response for an arbitrary URL even if you don't have internet access
With that in mind, I believe the best strategy is to contact several sites over an HTTPS connection and return true if any of those sites responds.
For example:
connected_to_internet() {
test_urls="\
https://www.google.com/ \
https://www.microsoft.com/ \
https://www.cloudflare.com/ \
"
processes="0"
pids=""
for test_url in $test_urls; do
curl --silent --head "$test_url" > /dev/null &
pids="$pids $!"
processes=$(($processes + 1))
done
while [ $processes -gt 0 ]; do
for pid in $pids; do
if ! ps | grep "^[[:blank:]]*$pid[[:blank:]]" > /dev/null; then
# Process no longer running
processes=$(($processes - 1))
pids=$(echo "$pids" | sed --regexp-extended "s/(^| )$pid($| )/ /g")
if wait $pid; then
# Success! We have a connection to at least one public site, so the
# internet is up. Ignore other exit statuses.
kill -TERM $pids > /dev/null 2>&1 || true
wait $pids
return 0
fi
fi
done
# wait -n $pids # Better than sleep, but not supported on all systems
sleep 0.1
done
return 1
}
Usage:
if connected_to_internet; then
echo "Connected to internet"
else
echo "No internet connection"
fi
Some notes about this approach:
It is robust against all the false positives and negatives I outlined above
The requests all happen in parallel to maximize speed
It will return false if you technically have internet access but DNS is non-functional or your network settings are otherwise messed up, which I think is a reasonable thing to do in most cases
If you want to handle captive portals, you can do this oneliner:
if [[ $(curl -s -D - http://www.gstatic.com/generate_204 2>/dev/null | head -1 | cut -d' ' -f 2) == "204" ]]; then
echo 'online'
else
echo 'offline'
fi
Or if you want something more readable that can differentiate captive portals from lack of signal:
function is_online() {
# Test signal
local response
response=$(curl --silent --dump-header - http://www.gstatic.com/generate_204 2> /dev/null)
if (($? != 0)); then return 2; fi
# Test captive portal
local status=$(echo $response | head -1 | cut -d' ' -f 2)
((status == "204"))
}
is_online && echo online || echo offline