is there a way to get peak memory of a process on Mac and Linux with the same shell command?
Right now I have such logic working on Linix:
/usr/bin/time -f "%M" myProc 2>$1 | tee memory | tail -n 1 "$log" | int($1)
where time -f "%M" changes the output of time to only show peak memory and the rest is getting the value as an integer.
Now I need to do the same for Mac but it does not understand -f, I have tried to use
TIMEFMT='%M'
time myProc 2>$1 | tee memory
but it stopped working on Linux and had bunch of extra ouput on Mac.
Is there a way to do it better without installing additional dependencies?
Thanks.
Hello I have a memory leak on my server which I finding it difficult to trace, apparently so is support. They told me I to try and write a cron to detect when my server is low on memory but I have no idea how to do this.
I use PHP to build my apps on a VPS server with CentOS6 installed..
Quoting from https://cookbook.wdt.io/memory.html:
free is a standard unix command that displays used and available memory. Used with the options -m it will output the values in megabytes. The last value in the line labeled "-/+ buffers/cache:" shows the total available memory. So we can use grep and awk to get this value and turn it into a number.
free -m | grep cache: | awk '{ print int($NF) }'
*/5 * * * * ((`free -m | grep cache: | awk '{ print int($NF) }'` >= 50)) && curl -sm 30 http://any_monitoring_url
The "curl ... any_monitoring_url" in the above example is pinging an external monitoring system like the one we built (wdt.io) to catch memory leaks and then email / sms / slack you. This step is not strictly necessary. You could do something as simple as touch file_to_check_timestamp or echo "Low Memory!" >> file_to_check_for_low_memory_alerts. The problem is that if memory (or CPU or disk space) get pinned, you could hit deadlock and the scheduled cron task may not run. Hence the value of a third-party monitor.
Also see our articles on cron monitoring CPU and Disk Space and other recipes, in case they're of value as well.
Hello I am trying to secure a linux machine that I have built.
I want to prevent people from clonning the hard disk drive.
I have a script that runs with init on startup and every 1 hour.
Script is something like this. It has hard coded hard disk drive serial number, motherboard serial number and few other serials. Script checks the serial of number of the hard drive and mother against hard coded serial. If it does not match. It sends a halt message to the system and the system shuts down.
Now I want to display a message on the connected display / monitor before halting the system. Obviously user wont be logged on when this happens. So I am looking for a way to send the message to the screen without logging.
Here is the script snippet.
#!/bin/bash
$coded-hdserial="W4837486938473ASD534354"
$coded-mbserial="XFD6345-32423-IRJDFJDF-234823729"
$check-hdserial=`smartctl -i /dev/sda | grep "Serial Number" | awk -F ":" {'print $2'} | sed -e 's/^[ \t]*//'`
$check-mbserial=`lshw | grep -A 15 "*-core" | grep "serial:" | awk -F ":" {'print $2'} |sed -e 's/^[ \t]*//' | tr -d '.'`
if
$coded-hdserial == $check-hdserial
then
echo "OK" >/dev/null 2>&1
else
echo "This copy of the software cannot be validated, it may be is a counterfeit. Therefore you cannot continue to enjoy the privilege to use this software. Please contact the support for further information.
This system will now be shut down. Further attempts to make counterfeit or duplicate copies of this system will initiate the self destruction and you will loose all data."
halt in 1 minute
fi
if
$coded-mbserial == $check-mbserial
then
echo "OK" >/dev/null 2>&1
else
echo "This copy of the software cannot be validated, it may be is a counterfeit. Therefore you cannot continue to enjoy the privilege to use this software. Please contact the support for further information.
This system will now be shut down. Further attempts to make counterfeit or duplicate copies of this system will initiate the self destruction and you will loose all data."
halt in 1 minute
fi
My question how can I display a good nice looking warning message to connected monitor. Or probably a JPG image on the screen with warning.
Look at kernel support for frame buffer devices to which you might be able to dump raw pixel data like from a bitmap image file. This is how the GRand Unified Bootloader (GRUB) makes a graphical boot menu. No need for X, but you won't get actual dialog windows. If you want a lightweight ASCII art interactive menu system, look at a Curses implementations like ncurses.
I wrote a script for checking the disk space in the linux machine using shell script when i am login.
Now if i am not login in that machine but i need an alert if the disk space is more than the threshold (ex:80) means how can i check?
1.Using ssh (remote command execution)
2.Run as a background script.
Which one is more efficient?
or is there any other ideas to do this?
I do not want to do any kind of login directly/indirectly. ie. I even don't want to use ssh keygen to store keys. It should work like the webpages, with any new systems also but without any kind of security tuning
Pls let me know.
The cron program is a good place to start. It is available on any Linux system, and can be setup to run programs at regular intervals. If the program produces error messages, those are normally emailed to the account which create the cron job.
Script for checking the disk usage and cpu usage
ALERT=60
df command is used to check the list of disks available and their attributes.Here we get the Filesystem information and take name of the file system and usage of the file
system through awk command.Next for getting the value we cut the % symbol and get the interger only.Then we check the condition for Alert Message.
df -H | grep -vE '^Filesystem' | awk '{ print $5 " " $1 }' | while read output; do
usep=$(echo $output | awk '{ print $1}'| cut -d '%' -f1 )
partition=$(echo $output | awk '{ print $2 }' )
if [ $usep -ge $ALERT ]; then
echo "Alert: Almost out of disk space $usep $partition $HOSTNAME"
fi
done
This is the script i have written for checking the disk space.
Then i gave crontab -e command in the terminal add the script to the file.Now the new cron job is assigned.i set the cronjob to be executed for every 1 hour to monitor the disk space check.
So,Now i can't able to get the message notification.If i am not logged in in that machine,How to get the information about the disk space check?
Is there any thing needs to improve in the script?
Is there any ready-to-use solution to log the memory consumption from the start of the system? I'd like to log the data to simple text file or some database so I can analyze it later.
I'm working on Linux 2.4-based embedded system. I need to debug the problem related to memory consumption. My application automatically start on every system start. I need the way to get the data with timestamps from regular intervals (as often as possible), so I can track down problem.
The symptoms of my problem: when system starts it launched my main application and GUI to visualize the main parameters of the system. GUI based on GTK+ (X server). If I disable GUI and X server then my application works OK. If I enable GUI and X server it does not work when I have 256 MiB or 512 MiB of physical memory installed on the motherboard. If I have 1 GiB of memory installed then everything is OK.
The following script prints time stamps and a header.
#!/bin/bash -e
echo " date time $(free -m | grep total | sed -E 's/^ (.*)/\1/g')"
while true; do
echo "$(date '+%Y-%m-%d %H:%M:%S') $(free -m | grep Mem: | sed 's/Mem://g')"
sleep 1
done
The output looks like this (tested on Ubuntu 15.04, 64-bit).
date time total used free shared buffers cached
2015-08-01 13:57:27 24002 13283 10718 522 693 2308
2015-08-01 13:57:28 24002 13321 10680 522 693 2308
2015-08-01 13:57:29 24002 13355 10646 522 693 2308
2015-08-01 13:57:30 24002 13353 10648 522 693 2308
A small script like
rm memory.log
while true; do free >> memory.log; sleep 1; done
I am a big fan of logging everything and I find it useful to know which processes are using the memory and how much each process is using (as well as sumary statistics). The following command records a top printout ordered by memory consumption every 0.5 seconds:
top -bd0.5 -o +%MEM > memory.log
Just note that the log file will grow a lot faster than if you only store the total memory utilization statistics so be sure you don't run out of disk space.
There's a program called
sar
on *nix systems. You could try to use that to monitor memory usage. It takes measurements at regular intervals. Do a
man sar
for more details. I think the option is -r for taking memory measurements, -i to specify the interval you'd like.
I think adding a crontab entry will be enough
*/5 * * * * free -m >> some_output_file
There are other tools like SeaLion, New Relic, Server Density etc which will almost do the same but are much easier to install and configure. My favorite is SeaLion, as it being free and also it gives a awesome timeline view of raw outputs of common linux commands.
You could put something like
vmstat X >> mylogfile
into a startup script. Since your application is already in startup you could just add this line to the end of the initialization script your application is already using.
(where X is # of seconds between log messages)
To periodically log the memory usage efficiently, I combined another answer here with a method to only retain the top-K memory-using processes.
top -bd 1.5 -o +%MEM | grep "load average" -A 9 > memory_usage.log
This command will record, every 1.5s, the top header information and the 3 highest memory-consuming processes (there's a 6-line offset for top's header information). This saves lots of disk space over recording top's information for every process.
So I know that I am late to this game, but I just came up with this answer, as I needed to do this, and really didn't want the extra fields that vmstat, free, etc... all will seem to output without excess filtering. So here is the answer that I came up with:
top -bd 0.1 | grep 'KiB Mem' | cut -d' ' -f10 > memory.txt
OR:
top -bd 0.1 | grep 'KiB Mem' | cut -d' ' -f10 | tee memory.txt
the standard output from top when grep ing with Kib Mem is:
KiB Mem : 16047368 total, 8708172 free, 6015720 used, 1323476 buff/cache
By running this through cut, we filter down to literally just the number prior to used
The user can indeed modify the 0.1 to another number in order to run different capture sample rates. In my case I wanted to use top also because you can run memory stats faster than 1 second per capture, as you can see here I wanted to capture a stat every 1/10th of a second.
NOTES:
It does turn out that piping through cut cause MASSIVE delay in getting anything out to file. As we later found out, it is much faster to leave out the cut command during data acquisition, then perform the cut command on the output file later.
Also, we had no need for timestamps in our tests.
This thus looks as follows:
Begin Logging:
top -bd 0.1 | grep 'KiB Mem' | tee memory_raw.txt
Exit Logging:
ctrl-z (to exit logging)
Filter:
2 levels of cut (filtering), first by comma, then by space. This is due to the alignment of top and provides much cleaner output:
cut memory_raw -d',' -f3 | tee memory_used_withlabel.txt
cut memory_used_withlabel.txt -d' ' -f3 | tee memory_used.txt