Tech Talks

#!/bin/bash # Script to create a CSV formatted text with a file of a few lines having one entry per line. # This will merge the files line by line for i in `cat test`; do echo $i > out/$i.out; done; paste -d, out/*

Password less SSH using RSA/DSA public key helps a lot in automated file copying, scripts, cron, etc. but there found a trouble when a root equivalent user will try this mechanism. It wont work if you just copy/append the public key to remote server's ~/.ssh/authorized_keys. The wrong thing here is when you generate public key it will make one with username root instead of the real user's name since the UID is 0. The hack to be done to fix this is just change the username at the end of the public key in authorized_keys at remote server. . Change the username entry of Public key at remote location in authorized_keys from root to USER. If you have a single entry in authorized_keys you can run the below command. Otherwise open it in an editor and replace the ROOT with USERNAME for the specific key. # sed -i 's/root/USER/g' /home/USER/.ssh/authorized_keys Other general things to be taken care in SSH key mechanism are · Set user and group of /home/USER to

#!/bin/bash # Author: haritux.in # To be ran as root or SUDO echo Enter the destination directory for backup read DEST OUT=`hostname`_crons.`date +%d%m%Y-%H%M%S` mkdir -p $DEST/$OUT 2&> /dev/null cd $DEST/$OUT for i in `ls /var/spool/cron/crontabs/`  ### Debian, Ubuntu #for i in `ls /var/spool/cron/`  ### Red Hat, CentOS, Fedora    do       grep $i /etc/passwd      if [ $? = 0 ]; then         {         crontab -u $i -l >> $i.cronlist.txt         }      fi    done cd .. tar -czf $OUT.tar.gz2 $OUT rm -rf $OUT

#!/bin/bash echo Select the hostname to SSH HOSTS=/home/psychotux/scripts/conf/hosts.txt cat $HOSTS | cut -f3 -d'|' read host echo Enter your username number IP=`grep $host $HOSTS | cut -f2 -d'|'` ssh "$user"@$IP Note: /home/psychotux/scripts/conf/hosts.txt will be a file with values HOSTNAME and IP ADDRESS separated by "|"