https://medjava.ro/ 2026-04-05T19:28:23+00:00 https://medjava.ro/ https://medjava.ro/lib/exe/fetch.php?media=wiki:dokuwiki.svg text/html 2025-11-19T23:10:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:check-hdd-health&rev=1763593847&do=diff Linux HDD Diagnostics & Health Check This guide outlines the steps to diagnose hard drive issues, ranging from system freezes (I/O Wait) to physical hardware failure. Step 1: Is the Disk Slowing Down the System? Before checking the disk physically, check if the disk is the bottleneck causing system lag or text/html 2023-07-04T16:36:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:check-ssd-health&rev=1688488590&do=diff Check SSD health on linux Important to check (value 100 is ideal - it will decrease under 100 over time): * Power_On_Hours - how many hours the drive has been powered on * Wear_Leveling_Count - remaining drive endurance Short test: smartctl -t short -a /dev/sdc text/html 2023-07-04T16:36:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:copy-preserve-rights&rev=1688488590&do=diff Synchronize two local folders rsync -avz --delete /media/usb/* /home/partimag Copy recursively a folder and keep original rights cp -a /data1/* /bkpdata1 Diff between two folders recursively diff -rq /data1 /bkpdata1 text/html 2025-01-02T18:22:18+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:display-specific-line-from-a-large-file&rev=1735842138&do=diff Display a specific line from a very large file sed -n '2130876p' sample.csv text/html 2024-02-15T21:13:32+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:fail2ban&rev=1708031612&do=diff Fail2Ban Commands List all banned IP's on all services (jails) for jail in $(sudo fail2ban-client status | grep 'Jail list:' | sed -r 's/.*Jail list://; s/,//g'); do echo "Jail: $jail"; sudo fail2ban-client status "$jail" | grep 'Banned IP list'; echo; done text/html 2023-07-04T16:36:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:generate-csr&rev=1688488590&do=diff Generate CSR (Certificate Signing Request) openssl req -new -newkey rsa:2048 -nodes -keyout medjava.ro.key -out medjava.ro.csr Send mail with attachments mail -s "CSR Files" -a phab.ro.csr -a nocloud.ro.csr odefta@medjava.ro < message.txt * CSR Files is the subject text/html 2023-07-04T16:36:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:owncloud&rev=1688488590&do=diff Turn off maintenance mode (after upgrade) cd /var/www/html/owncloud sudo -u apache php occ upgrade sudo -u apache php occ maintenance:mode --off text/html 2025-01-02T18:22:18+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:replace-characters-in-large-files&rev=1735842138&do=diff Replace characters in very large files We can use the sed command. Example - replace “” with “: sed -i 's/""/"/g' sample.csv Get rid of all ”: sed -i 's/"//g' sample.csv Get rid of “ on the first line only: sed -i '1s/"//g' sample.csv text/html 2025-11-19T22:03:56+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:sync-non-blocking&rev=1763589836&do=diff Safe Data Migration under High I/O Load Use this method when you need to transfer data from a storage device that is already under heavy load (e.g., RAID resync, slow USB, high latency) to prevent system lockups (high I/O Wait). The Command ionice -c 3 rsync -avxW --progress /source/path/ /destination/path/ text/html 2023-07-04T16:36:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://medjava.ro/doku.php?id=linux:tar&rev=1688488590&do=diff Remove a single file from a tar archive tar --delete -f cygwin.tar lib/libexpat.dll.a Archive entire folder tar -zcvf plugins.tar.gz plugins