1. List disk space usage:
df -hl // "l" means "local", limit listing to local file systems // "h" means "human-readable", print sizes in human readable format du -cks *|sort -rn|head // recurisive sort file size under current folder
2. Sort file by size:
ls -hlS // "h": "human-readable", print sizes in human readable format // "l" : use a long listing format // "S": sort by file size // "t" : sort by modification date // "r" : reverse order while sorting // "s" : size, with "-l" print size of each file, in blocks // For file, the output is the size of the file. // For directory, the output is fixed 4.0K.
3. Delete file by size:
find . -size +10240k -exec rm -rf {} \;
4. Delete file by date:
find . -mtime +5 -exec rm -rf {} \;
5. Overview of CPU, I/O, Memory:
> vmstat procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 778576 337756 3527900 0 0 1 21 0 0 1 0 98 1 0 // Processes: // r: The number of processes waiting for runtime. // b: The number of processes in uninterruptible sleep. // Memory: // swpd: The amount of virtual memory used. // free : The amount of idle memory // buff : The amount of memory used as buffers. // cache: the amout of memory used as cache. // Disk/Memory Swap: // si: Amount of memory swapped from disk. // so: Amount of memory swapped to disk. // I/O: // bi: Blocks received from a block device // bo: Blocks sent to a block device // System: // in: The number of interrupts per second, including the clock // cs: The number of context switches per second // CPU: // us: Time spent runnning non-kernel code. (user time) // sy: Time spent running kernel code. (system time) // id: Time spent idel. // wa: Time spent waiting for IO // st: Time stolen from a virtual machine.
6. Brief overview of system load average
>uptime 03:33:32 up 271 days, 9:44, 1 user, load average: 0.93, 1.06, 0.99 // 0.93 is the load average for last 1 minute // 1.06 is the load average for last 5 minutes // 0.99 is the load average for last 15 minutes // Command above should usually used combine with command below: > grep 'model name' /proc/cpuinfo model name : Intel(R) Xeon(R) CPU X5650 @ 2.67GHz model name : Intel(R) Xeon(R) CPU X5650 @ 2.67GHz // Means our system are 2-core machine.
7. Real time CPU/Memory/Load Average usage monitor:
> top top - 03:58:40 up 151 days, 18:50, 4 users, load average: 0.78, 0.67, 0.28 Tasks: 157 total, 1 running, 156 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.1%sy, 0.0%ni, 99.0%id, 0.8%wa, 0.0%hi, 0.1%si, 0.0%st Mem: 8174448k total, 4369796k used, 3804652k free, 138580k buffers Swap: 0k total, 0k used, 0k free, 1491884k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 16267 rcastdev 15 0 10888 1104 800 R 0.3 0.0 0:00.01 top 16769 root 15 0 0 0 0 S 0.3 0.0 0:06.31 pdflush
8. Network statistical info:
> netstat -s
> netstat -pt // -p: show PID which possess the port number // t: show TCP protocol only Proto Recv-Q Send-Q Local Address Foreign Address State PID tcp 0 0 ***.***:23010 ***.***:43333 ESTABLISHED 123
9. Memory statistical info:
> free
total used free shared buffers cached
Mem: 8174448 4369228 3805220 0 138664 1492784
-/+ buffers/cache: 2737780 5436668
Swap: 0 0 0
10. SCP:
// SCP local file to remote:
scp {local-file} {username}@{remote-machine}:{remote-dir}
// SCP remote file to local:
scp {username}@{remote-machine}:{remote-file} {local-dir}
Reference Links:
1> Load average: http://blog.scoutapp.com/articles/2009/07/31/understanding-load-averages
2> SCP: http://www.hypexr.org/linux_scp_help.php