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Tag: linux

Chain SSH script

Let’s say I have 3 linux servers. I need a script that will login from s1 to s2 via ssh, then from s2 to s3 via ssh, then check, if there is already exists string in ~/.ssh/authorized_keys from s1 then do nothing otherwise do s1 and s2 are constant, s3 can be variable. ssh from s1 to s2 already settled

How to replace newlines between brackets

I have log file similar to this format Here is the echo command to produce that output $ echo -e “test {nseq-cont {nttt0,nttt67,nttt266nttt},nttgrp-id 505nt}n}ntest{nttest1{nttvalnt}n}n” Question is how to remove all whitespace between seq-cont { and the next } that may be multiple in the file. I …

Root privileges needed for “systemctl suspend” command

On an embedded Linux device (Colibri module with an iMX7d processor) I am not able to run the command systemctl suspend as an non-root user in order to switch into suspend mode. When I log in as root user, the command is executed and the system switches to suspend mode. The same command runs on a Ubuntu PC sy…

run a command with a file pattern

I have this file patterns.txt And I want to run a specific command for every pattern like this: I tried to used for loop like this: but i didn’t work Answer The 2 typical approaches are: and Note that I would expect both of those to fail, since scp expects at least 2 arguments. How you want that 2nd arg…

Restart Opencanary from Crontab

I have a programm called opencanary running at a virtual environment at my Raspberry Pi with Ubuntu 18.04 installed. I want to restart it every 30 Minutes using crontab. For testing I set the script to run every 3 Minutes as you can see below. When I execute the script manually it’s working fine. When u…

Protecting against Time-of-check to time-of-use?

I was reading: https://en.wikipedia.org/wiki/Time-of-check_to_time-of-use They showed this code to be buggy and I totally understand why it’s so: But the real question is how to protect against this type of exploits? Answer You can use the O_NOFOLLOW flag. It will cause the open to fail if basename of t…