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To get detailed information on the CPU, use this command:

cat /proc/cpuinfo

The output will look similar to this:

cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 107
model name      : AMD Athlon(tm) 64 X2 Dual Core Processor 5600+
stepping        : 2
cpu MHz         : 2900.171
cache size      : 512 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm cr8legacy ts fid vid ttp tm stc [6]
bogomips        : 5945.45

Get detailted information on memory usage:

cat /proc/meminfo

MemTotal:      4116112 kB
MemFree:        470164 kB
Buffers:        154592 kB
Cached:        1658332 kB
SwapCached:        488 kB
Active:        2304500 kB
Inactive:      1017644 kB
HighTotal:     3243840 kB
HighFree:       183672 kB
LowTotal:       872272 kB
LowFree:        286492 kB
SwapTotal:     4200888 kB
SwapFree:      4197128 kB
Dirty:            4764 kB
Writeback:           0 kB
AnonPages:     1378960 kB
Mapped:         135580 kB
Slab:           289720 kB
PageTables:      16680 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:   6258944 kB
Committed_AS: 3779921956 kB
VmallocTotal:   118776 kB
VmallocUsed:     11892 kB
VmallocChunk:   106628 kB

Information about disk usage

df -h

df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md2              375G   41G  315G  12% /
tmpfs                 2.0G     0  2.0G   0% /lib/init/rw
udev                   10M   52K   10M   1% /dev
tmpfs                 2.0G     0  2.0G   0% /dev/shm
/dev/md1              510M   37M  448M   8% /boot

And the partitions:

fdisk -l

Disk /dev/sda: 85.8 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000d6430

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       10255    82373256   83  Linux
/dev/sda2           10256       10443     1510110    5  Extended
/dev/sda5           10256       10443     1510078+  82  Linux swap / Solaris

Many linux servers are administered on the commandline e.g. with a SSH connection. In the following article, I will explain several shell commands that make it easy to view logfiles.

The most important command is “tail”. Tail can be used to read the last lines from a file. Examples:

Get the last 100 lines from the Debian mail log file:

tail -n 100 /var/log/mail.log

To get all newly added lines from a log file in realtime on the shell, use the command:

tail -f /var/log/mail.log

to quit tail and go back to the commanline press the keys [ctrl] + [c]

If you want to get the last 1000 lines from a log file and they do not fit into your shell window, you can use the command “more” to be able to view them line by line.

tail -n 1000 /var/log/mail.log | more

press [space] to go to the next line or [ctrl] + [c] to quit.

If you want to search for a specific term in a large file, the command “grep” comes in handy. Example: We search for the email address “tom@anydomain.tld” in the mail log file:

grep “tom@anydomain.tld” /var/log/mail.log

If you want to view the whole content of file on the shell, use the command “cat”. Example:

cat /proc/cpuinfo

will show you detailed info about the CPU of your computer.