{"id":132,"date":"2013-03-11T22:17:48","date_gmt":"2013-03-11T22:17:48","guid":{"rendered":"http:\/\/knowledge.fastsimple.com\/wordpress\/linux"},"modified":"2022-01-21T15:52:43","modified_gmt":"2022-01-21T15:52:43","slug":"linux","status":"publish","type":"page","link":"https:\/\/knowledge.fastsimple.com\/wordpress\/webdesktop\/linux\/","title":{"rendered":"Linux"},"content":{"rendered":"

List waiting processes<\/h3>\n
ps -edalf | grep cv_wai<\/pre>\n
Recursively grep source files<\/h3>\n
grep -r --include=\"*.php\" \"something\" .\/<\/pre>\n
Cleanup old backups<\/h3>\n
find \/bigdata\/backups_day\/*tgz -mtime +22 -exec rm {} \\;<\/pre>\n
Global search replace<\/h3>\n
perl -p -i -e 's\/oldstring\/newstring\/g' `find . | grep [.]php`<\/pre>\n
Find often running executables (useful to determine load average bottlenecks)<\/h3>\n
ps aux | awk '{print $11}' | sort | uniq -c | sort -nk1 | tail -n5<\/pre>\n
\u00a0Detect incomming connections (analyze potential DOS attacks)<\/h3>\n
netstat -an | grep :80 | awk '{print $5}' | cut -f1 -d\":\" | sort | uniq -c | sort -n<\/pre>\n
Find space eating folders<\/h3>\n
for i in T G M; do du -ah 2>&1 | grep \"^[0-9.]*$i\" | sort -nr -k 1; done | head -n 25<\/pre>\n
Test disk speed (TransIP 530 MB\/s, Vultr 460 MB\/s, Digital Ocean 307 MB\/s)<\/h3>\n
dd if=\/dev\/zero of=test bs=64k count=16k conv=fdatasync<\/pre>\n
Auto restart apache (crontab -e)<\/h3>\n
* * * * * if [[ `wget --tries=1 --timeout=30 -qO- http:\/\/???\/quickcheck.php` != \"OK\" ]]; then \/sbin\/service httpd restart; fi<\/pre>\n
Log server load (requires iotop, usable as root crontab entry)<\/h3>\n
(echo `date` ; echo ; \/usr\/*bin\/iotop -b -n 2 | sed -n '1,10 d;\/^Total DISK READ\/,\/\/ p' | sed '11,$d' ; echo ; top -b -n 1 | head -n 20 ; echo ) >> \/var\/log\/toptop-`date +\\%Y\\%m`.log<\/pre>\n
Prevent a script from running simultaneously<\/h3>\n
(\r\n  flock -x -n 200 || exit 1\r\n  echo Doing stuff\r\n  sleep 3\r\n  echo Done doing stuff\r\n) 200>\/var\/lock\/.myscript.exclusivelock<\/pre>\n
SSH login without password (usually\u00a0ssh-copy-id \u00a0will do all this for you)<\/h3>\n