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| technology:unix:useful_commands 12.22.2009 23:28 | technology:unix:useful_commands 03.18.2013 05:53 current | ||
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| ====== Useful commands ====== | ====== Useful commands ====== | ||
| <code shell> | <code shell> | ||
| - | top ; shows running processes; 'c' = see process details; 'q' = quit; '1' = show processor cores; 'k' = kill a process | + | = Performance = |
| + | top ; shows running processes; | ||
| + | 'c' = see process details; '1' = show processor cores; 'k' = kill a process | ||
| + | 'A' = show many windows; 'a,w' = navigate windows; 'z' = color; 'x' = highlight sort col | ||
| + | shift-w = save it too your .toprc | ||
| + | = Finding Stuff = | ||
| + | find / -name "file_name" -print ; find file name from root directory path (/) | ||
| + | find . -user root ; find files owned by root user, in current directory (.) | ||
| + | locate -i fstab ; find file name in database that keeps track of filenames | ||
| + | find . -type f -user zenoss -name "*.py" -exec grep -il "blah" {} \; | ||
| + | ; find text "blah" in .py files belonging to zenoss user | ||
| + | locate Data.fs | xargs ls -l ; xargs to pipe results of one command to another | ||
| + | find ./ -name '*py' | xargs grep signal ; Find string "signal" inside text of .py files; xargs looks inside the files instead of at the file name | ||
| + | grep -ir "timeout" . ; find the string "timeout" in any file below the current dir | ||
| + | |||
| + | = Various = | ||
| screen ; lets you share screens with other people | screen ; lets you share screens with other people | ||
| nano ; text editor that lets you use modern keyboard keys | nano ; text editor that lets you use modern keyboard keys | ||
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| ps axo pid,tty,stat,bsdstart,bsdtime,command ; list processes with time started and cpu time taken | ps axo pid,tty,stat,bsdstart,bsdtime,command ; list processes with time started and cpu time taken | ||
| ps -aux ; easier process list, alsp try without the '-' | ps -aux ; easier process list, alsp try without the '-' | ||
| - | ps -ef ; short columned process list (less fields returned per process) | + | ps -ef ; short columned process list (less fields returned) |
| - | smbd & ; postfix any command with '&' to have it run in the background | + | smbd & ; postfix with '&' to have it run in the background |
| wget <http url> ; download a file from the web | wget <http url> ; download a file from the web | ||
| sar ; system activity reporter | sar ; system activity reporter | ||
| - | find / -name "file_name" -print ; find file name from root directory path (/) | + | |
| - | find . -user root ; find files owned by root user, in current directory (.) | + | |
| - | locate -i fstab ; find file name in database that keeps track of filenames; same as above, MUCH easier | + | |
| - | find . -type f -user zenoss -name "*.py" -exec grep -il "blah" {} \; | + | |
| - | ; find text "blah" in files belonging to zenoss user, extension .py | + | |
| du -k ~ | more ; show disk usage (useful for over quota) for home directory | du -k ~ | more ; show disk usage (useful for over quota) for home directory | ||
| du -h --max-depth=1 . | sort -rn ; show totalled directory sizes for current dir | du -h --max-depth=1 . | sort -rn ; show totalled directory sizes for current dir | ||
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| chkconfig ; services on / off | chkconfig ; services on / off | ||
| crontab -l ; list the existing cron instances | crontab -l ; list the existing cron instances | ||
| + | crontab -e ; add crontab entries for current user | ||
| dmesg | more ; print out bootup messages / kernel ring buffer | dmesg | more ; print out bootup messages / kernel ring buffer | ||
| whoami ; tells you who you are currently logged in as | whoami ; tells you who you are currently logged in as | ||
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| service smtpd status/stop/start ; Email service stop/start; /var/log/maillog for some debug info | service smtpd status/stop/start ; Email service stop/start; /var/log/maillog for some debug info | ||
| for i in *.txt; do mv "$i" `basename $i .txt`.doc; done ; Rename all txt files to doc | for i in *.txt; do mv "$i" `basename $i .txt`.doc; done ; Rename all txt files to doc | ||
| + | /usr/bin/ssh -i ~/.ssh/id_dsa server_name "ls" ; run command on another server and get results; id_dsa is ref to PKI login info... no passwd needed | ||
| + | ps -A -o pid,state,command | grep D ; find process that's blocking due to IO wait | ||
| + | ; 'D' is for Delayed processes, IO wait is most common cause | ||
| - | File System Manipulation | + | |
| + | = File System Manipulation = | ||
| fuser -m /dev/md0 ; shows processes being used by device | fuser -m /dev/md0 ; shows processes being used by device | ||
| lsof /media/documents/ ; show list of files open | lsof /media/documents/ ; show list of files open | ||
| lsof / | grep media ; in case above doesnt work, lsof seems to work better on root and then grep it out for what you need | lsof / | grep media ; in case above doesnt work, lsof seems to work better on root and then grep it out for what you need | ||
| + | lsof +D /var/log/ ; list of files open under the given directory (recursive) (use +d for non-recurse) | ||
| - | Network Information | + | |
| + | = Network Information = | ||
| nslookup 10.175.211.10 ; reverse DNS lookup; gives the hostname associated with the IP | nslookup 10.175.211.10 ; reverse DNS lookup; gives the hostname associated with the IP | ||
| host -a www.google.com ; DNS lookup; gives IP associated with the hostname (verbose) | host -a www.google.com ; DNS lookup; gives IP associated with the hostname (verbose) | ||
| dig ns zenoss.loc ; gives nameserver of domain | dig ns zenoss.loc ; gives nameserver of domain | ||
| netstat -anp | grep 8082 ; will tell you what process is listening at 8082, if any | netstat -anp | grep 8082 ; will tell you what process is listening at 8082, if any | ||
| + | netstat -an | grep LIST ; show listening ports (LIST = LISTEN) | ||
| tcpdump ip proto ICMP ; shows you what ping requests are being send and received, realtime | tcpdump ip proto ICMP ; shows you what ping requests are being send and received, realtime | ||
| + | tcpdump port 80 or port 443 ; shows traffic in and out on http and https | ||
| + | echo “newhostname” > /proc/sys/kernel/hostname ; set new hostname on CentOS / RedHat | ||
| + | netstat -rn ; routing table | ||
| + | |||
| - | Package Management | + | = Package Management = |
| rpm -qa ; Packages installed on system | rpm -qa ; Packages installed on system | ||
| + | rpm -qa | grep httpd* ; See if httpd is installed | ||
| + | yum list installed httpd ; See if httpd is installed | ||
| yum provides /etc/fstab ; name of the package which contains a particular file | yum provides /etc/fstab ; name of the package which contains a particular file | ||
| yum list ; lists information about available packages | yum list ; lists information about available packages | ||
| yum install gnote ; install gnote and all its dependancies | yum install gnote ; install gnote and all its dependancies | ||
| + | patch < /patch/to/apply.diff | ||
| + | patch -R --dry-run --verbose < patch.diff ; undo / backout a patch | ||
| + | yast ; opensolaris / SLES package manager | ||
| </code> | </code> | ||