This is a linux command line reference for common operations.
Command and Description
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apropos whatis
Show commands pertinent to string. See also threadsafe
•
man -t man | ps2pdf - > man.pdf
make a pdf of a manual page
which command
Show full path name of command
time command
See how long a command takes
•
time cat
Start stopwatch. Ctrl-d to stop. See also sw
•
nice info
Run a low priority command (The "info" reader in this case)
•
renice 19 -p $$
Make shell (script) low priority. Use for non interactive tasks
dir navigation
•
cd -
Go to previous directory
•
cd
Go to $HOME directory
(cd dir && command)
Go to dir, execute command and return to current dir
•
pushd .
Put current dir on stack so you can popd back to it
file searching
•
alias l='ls -l --color=auto'
quick dir listing
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ls -lrt
List files by date. See also newest and find_mm_yyyy
•
ls /usr/bin | pr -T9 -W$COLUMNS
Print in 9 columns to width of terminal
find -name '*.[ch]' | xargs grep -E 'expr'
Search 'expr' in this dir and below. See also findrepo
find -type f -print0 | xargs -r0 grep -F 'example'
Search all regular files for 'example' in this dir and below
find -maxdepth 1 -type f | xargs grep -F 'example'
Search all regular files for 'example' in this dir
find -maxdepth 1 -type d | while read dir; do echo $dir; echo cmd2; done
Process each item with multiple commands (in while loop)
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find -type f ! -perm -444
Find files not readable by all (useful for web site)
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find -type d ! -perm -111
Find dirs not accessible by all (useful for web site)
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locate -r 'file[^/]*\.txt'
Search cached index for names. This re is like glob *file*.txt
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look reference
Quickly search (sorted) dictionary for prefix
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grep --color reference /usr/share/dict/words
Highlight occurances of regular expression in dictionary
archives and compression
gpg -c file
Encrypt file
gpg file.gpg
Decrypt file
tar -c dir/ | bzip2 > dir.tar.bz2
Make compressed archive of dir/
bzip2 -dc dir.tar.bz2 | tar -x
Extract archive (use gzip instead of bzip2 for tar.gz files)
tar -c dir/ | gzip | gpg -c | ssh user@remote 'dd of=dir.tar.gz.gpg'
Make encrypted archive of dir/ on remote machine
find dir/ -name '*.txt' | tar -c --files-from=- | bzip2 > dir_txt.tar.bz2
Make archive of subset of dir/ and below
find dir/ -name '*.txt' | xargs cp -a --target-directory=dir_txt/ --parents
Make copy of subset of dir/ and below
( tar -c /dir/to/copy ) | ( cd /where/to/ && tar -x -p )
Copy (with permissions) copy/ dir to /where/to/ dir
( cd /dir/to/copy && tar -c . ) | ( cd /where/to/ && tar -x -p )
Copy (with permissions) contents of copy/ dir to /where/to/
( tar -c /dir/to/copy ) | ssh -C user@remote 'cd /where/to/ && tar -x -p'
Copy (with permissions) copy/ dir to remote:/where/to/ dir
dd bs=1M if=/dev/sda | gzip | ssh user@remote 'dd of=sda.gz'
Backup harddisk to remote machine
rsync (Network efficient file copier: Use the --dry-run option for testing)
rsync -P rsync://rsync.server.com/path/to/file file
Only get diffs. Do multiple times for troublesome downloads
rsync --bwlimit=1000 fromfile tofile
Locally copy with rate limit. It's like nice for I/O
rsync -az -e ssh --delete ~/public_html/ remote.com:'~/public_html'
Mirror web site (using compression and encryption)
rsync -auz -e ssh remote:/dir/ . && rsync -auz -e ssh . remote:/dir/
Synchronize current directory with remote one
ssh (Secure SHell)
ssh $USER@$HOST command
Run command on $HOST as $USER (default command=shell)
•
ssh -f -Y $USER@$HOSTNAME xeyes
Run GUI command on $HOSTNAME as $USER
scp -p -r $USER@$HOST: file dir/
Copy with permissions to $USER's home directory on $HOST
ssh -g -L 8080:localhost:80 root@$HOST
Forward connections to $HOSTNAME:8080 out to $HOST:80
ssh -R 1434:imap:143 root@$HOST
Forward connections from $HOST:1434 in to imap:143
wget (multi purpose download tool)
•
(cd dir/ && wget -nd -pHEKk http://www.pixelbeat.org/cmdline.html)
Store local browsable version of a page to the current dir
wget -c http://www.example.com/large.file
Continue downloading a partially downloaded file
wget -r -nd -np -l1 -A '*.jpg' http://www.example.com/dir/
Download a set of files to the current directory
wget ftp://remote/file[1-9].iso/
FTP supports globbing directly
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wget -q -O- http://www.pixelbeat.org/timeline.html | grep 'a href' | head
Process output directly
echo 'wget url' | at 01:00
Download url at 1AM to current dir
wget --limit-rate=20k url
Do a low priority download (limit to 20KB/s in this case)
wget -nv --spider --force-html -i bookmarks.html
Check links in a file
wget --mirror http://www.example.com/
Efficiently update a local copy of a site (handy from cron)
networking (Note ifconfig, route, mii-tool, nslookup commands are obsolete)
ethtool eth0
Show status of ethernet interface eth0
ethtool --change eth0 autoneg off speed 100 duplex full
Manually set ethernet interface speed
iwconfig eth1
Show status of wireless interface eth1
iwconfig eth1 rate 1Mb/s fixed
Manually set wireless interface speed
•
iwlist scan
List wireless networks in range
•
ip link show
List network interfaces
ip link set dev eth0 name wan
Rename interface eth0 to wan
i
p link set dev eth0 up
Bring interface eth0 up (or down)
•
ip addr show
List addresses for interfaces
ip addr add 1.2.3.4/24 brd + dev eth0
Add (or del) ip and mask (255.255.255.0)
•
ip route show
List routing table
ip route add default via 1.2.3.254
Set default gateway to 1.2.3.254
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tc qdisc add dev lo root handle 1:0 netem delay 20msec
Add 20ms latency to loopback device (for testing)
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tc qdisc del dev lo root
Remove latency added above
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host pixelbeat.org
Lookup DNS ip address for name or vice versa
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hostname -i
Lookup local ip address (equivalent to host `hostname`)
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whois pixelbeat.org
Lookup whois info for hostname or ip address
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netstat -tupl
List internet services on a system
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netstat -tup
List active connections to/from system
windows networking (Note samba is the package that provides all this windows specific networking support)
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smbtree
Find windows machines. See also findsmb
nmblookup -A 1.2.3.4
Find the windows (netbios) name associated with ip address
smbclient -L windows_box
List shares on windows machine or samba server
mount -t smbfs -o fmask=666,guest //windows_box/share /mnt/share
Mount a windows share
echo 'message' | smbclient -M windows_box
Send popup to windows machine (off by default in XP sp2)
text manipulation (Note sed uses stdin and stdout. Newer versions support inplace editing with the -i option)
sed 's/string1/string2/g'
Replace string1 with string2
sed 's/\(.*\)1/\12/g'
Modify anystring1 to anystring2
sed '/ *#/d; /^ *$/d'
Remove comments and blank lines
sed ':a; /\\$/N; s/\\\n//; ta'
Concatenate lines with trailing \
sed 's/[ \t]*$//'
Remove trailing spaces from lines
sed 's/\([`"$\]\)/\\\1/g'
Escape shell metacharacters active within double quotes
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seq 10 | sed "s/^/ /; s/ *\(.\{7,\}\)/\1/"
Right align numbers
sed -n '1000{p;q}'
Print 1000th line
sed -n '10,20p;20q'
Print lines 10 to 20
sed -n 's/.*<title>\(.*\)<\/title>.*/\1/ip;T;q'
Extract title from HTML web page
sed -i 42d ~/.ssh/known_hosts
Delete a particular line
sort -t. -k1,1n -k2,2n -k3,3n -k4,4n
Sort IPV4 ip addresses
•
echo 'Test' | tr '[:lower:]' '[:upper:]'
Case conversion
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tr -dc '[:print:]' < /dev/urandom
Filter non printable characters
•
history | wc -l
Count lines
set operations (Note you can export LANG=C for speed. Also these assume no duplicate lines within a file)
sort file1 file2 | uniq
Union of unsorted files
sort file1 file2 | uniq -d
Intersection of unsorted files
sort file1 file1 file2 | uniq -u
Difference of unsorted files
sort file1 file2 | uniq -u
Symmetric Difference of unsorted files
join -t'\0' -a1 -a2 file1 file2
Union of sorted files
join -t'\0' file1 file2
Intersection of sorted files
join -t'\0' -v2 file1 file2
Difference of sorted files
join -t'\0' -v1 -v2 file1 file2
Symmetric Difference of sorted files
math
•
echo '(1 + sqrt(5))/2' | bc -l
Quick math (Calculate φ). See also bc
•
echo 'pad=20; min=64; (100*10^6)/((pad+min)*8)' | bc
More complex (int) e.g. This shows max FastE packet rate
•
echo 'pad=20; min=64; print (100E6)/((pad+min)*8)' | python
Python handles scientific notation
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echo 'pad=20; plot [64:1518] (100*10**6)/((pad+x)*8)' | gnuplot -persist
Plot FastE packet rate vs packet size
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echo 'obase=16; ibase=10; 64206' | bc
Base conversion (decimal to hexadecimal)
•
echo $((0x2dec))
Base conversion (hex to dec) ((shell arithmetic expansion))
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units -t '100m/9.58s' 'miles/hour'
Unit conversion (metric to imperial)
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units -t '500GB' 'GiB'
Unit conversion (SI to IEC prefixes)
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units -t '1 googol'
Definition lookup
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seq 100 | (tr '\n' +; echo 0) | bc
Add a column of numbers. See also add and funcpy
calendar
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cal -3
Display a calendar
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cal 9 1752
Display a calendar for a particular month year
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date -d fri
What date is it this friday. See also day
•
[ $(date -d "tomorrow" +%d) = "01" ] || exit
exit a script unless it's the last day of the month
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date --date='25 Dec' +%A
What day does xmas fall on, this year
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date --date='@2147483647'
Convert seconds since the epoch (1970-01-01 UTC) to date
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TZ='America/Los_Angeles' date
What time is it on west coast of US (use tzselect to find TZ)
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date --date='TZ="America/Los_Angeles" 09:00 next Fri'
What's the local time for 9AM next Friday on west coast US
echo "mail -s 'get the train' P@draigBrady.com < /dev/null" | at 17:45
Email reminder
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echo "DISPLAY=$DISPLAY xmessage cooker" | at "NOW + 30 minutes"
Popup reminder
locales
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printf "%'d\n" 1234
Print number with thousands grouping appropriate to locale
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BLOCK_SIZE=\'1 ls -l
get ls to do thousands grouping appropriate to locale
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echo "I live in `locale territory`"
Extract info from locale database
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LANG=en_IE.utf8 locale int_prefix
Lookup locale info for specific country. See also ccodes
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locale | cut -d= -f1 | xargs locale -kc | less
List fields available in locale database
recode (Obsoletes iconv, dos2unix, unix2dos)
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recode -l | less
Show available conversions (aliases on each line)
recode windows-1252.. file_to_change.txt
Windows "ansi" to local charset (auto does CRLF conversion)
recode utf-8/CRLF.. file_to_change.txt
Windows utf8 to local charset
recode iso-8859-15..utf8 file_to_change.txt
Latin9 (western europe) to utf8
recode ../b64 < file.txt > file.b64
Base64 encode
recode /qp.. < file.qp > file.txt
Quoted printable decode
recode ..HTML < file.txt > file.html
Text to HTML
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recode -lf windows-1252 | grep euro
Lookup table of characters
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echo -n 0x80 | recode latin-9/x1..dump
Show what a code represents in latin-9 charmap
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echo -n 0x20AC | recode ucs-2/x2..latin-9/x
Show latin-9 encoding
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echo -n 0x20AC | recode ucs-2/x2..utf-8/x
Show utf-8 encoding
CDs
gzip < /dev/cdrom > cdrom.iso.gz
Save copy of data cdrom
mkisofs -V LABEL -r dir | gzip > cdrom.iso.gz
Create cdrom image from contents of dir
mount -o loop cdrom.iso /mnt/dir
Mount the cdrom image at /mnt/dir (read only)
cdrecord -v dev=/dev/cdrom blank=fast
Clear a CDRW
gzip -dc cdrom.iso.gz | cdrecord -v dev=/dev/cdrom -
Burn cdrom image (use dev=ATAPI -scanbus to confirm dev)
cdparanoia -B
Rip audio tracks from CD to wav files in current dir
cdrecord -v dev=/dev/cdrom -audio -pad *.wav
Make audio CD from all wavs in current dir (see also cdrdao)
oggenc --tracknum='track' track.cdda.wav -o 'track.ogg'
Make ogg file from wav file
disk space (See also FSlint)
•
ls -lSr
Show files by size, biggest last
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du -s * | sort -k1,1rn | head
Show top disk users in current dir. See also dutop
•
df -h
Show free space on mounted filesystems
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df -i
Show free inodes on mounted filesystems
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fdisk -l
Show disks partitions sizes and types (run as root)
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rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1n
List all packages by installed size (Bytes) on rpm distros
•
dpkg-query -W -f='${Installed-Size;10}\t${Package}\n' | sort -k1,1n
List all packages by installed size (KBytes) on deb distros
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dd bs=1 seek=2TB if=/dev/null of=ext3.test
Create a large test file (taking no space). See also truncate
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> file
truncate data of file or create an empty file
monitoring/debugging
•
tail -f /var/log/messages
Monitor messages in a log file
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strace -c ls >/dev/null
Summarise/profile system calls made by command
•
strace -f -e open ls >/dev/null
List system calls made by command
•
ltrace -f -e getenv ls >/dev/null
List library calls made by command
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lsof -p $$
List paths that process id has open
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lsof ~
List processes that have specified path open
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tcpdump not port 22
Show network traffic except ssh. See also tcpdump_not_me
•
ps -e -o pid,args --forest
List processes in a hierarchy
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ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed '/^ 0.0 /d'
List processes by % cpu usage
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ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS
List processes by mem (KB) usage. See also ps_mem.py
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ps -C firefox-bin -L -o pid,tid,pcpu,state
List all threads for a particular process
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ps -p 1,2
List info for particular process IDs
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last reboot
Show system reboot history
•
free -m
Show amount of (remaining) RAM (-m displays in MB)
•
watch -n.1 'cat /proc/interrupts'
Watch changeable data continuously
system information (see also sysinfo) ('#' means root access is required)
•
uname -a
Show kernel version and system architecture
•
head -n1 /etc/issue
Show name and version of distribution
•
cat /proc/partitions
Show all partitions registered on the system
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grep MemTotal /proc/meminfo
Show RAM total seen by the system
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grep "model name" /proc/cpuinfo
Show CPU(s) info
•
lspci -tv
Show PCI info
•
lsusb -tv
Show USB info
•
mount | column -t
List mounted filesystems on the system (and align output)
•
grep -F capacity: /proc/acpi/battery/BAT0/info
Show state of cells in laptop battery
#
dmidecode -q | less
Display SMBIOS/DMI information
#
smartctl -A /dev/sda | grep Power_On_Hours
How long has this disk (system) been powered on in total
#
hdparm -i /dev/sda
Show info about disk sda
#
hdparm -tT /dev/sda
Do a read speed test on disk sda
#
badblocks -s /dev/sda
Test for unreadable blocks on disk sda
interactive (see also linux keyboard shortcuts)
•
readline
Line editor used by bash, python, bc, gnuplot, ...
•
screen
Virtual terminals with detach capability, ...
•
mc
Powerful file manager that can browse rpm, tar, ftp, ssh, ...
•
gnuplot
Interactive/scriptable graphing
•
links
Web browser
•
xdg-open .
open a file or url with the registered desktop application
miscellaneous
•
alias hd='od -Ax -tx1z -v'
Handy hexdump. (usage e.g.: • hd /proc/self/cmdline | less)
•
alias realpath='readlink -f'
Canonicalize path. (usage e.g.: • realpath ~/../$USER)
•
set | grep $USER
Search current environment
touch -c -t 0304050607 file
Set file timestamp (YYMMDDhhmm)
•
python -m SimpleHTTPServer
Serve current directory tree at http://$HOSTNAME:8000/
< The list of Vim commands >
Working with files
Vim command
Action
:e filename
Open a new file. You can use the Tab key for automatic file name completion, just like at the shell command prompt.
:w filename
Save changes to a file. If you don't specify a file name, Vim saves as the file name you were editing. For saving the file under a different name, specify the file name.
:q
Quit Vim. If you have unsaved changes, Vim refuses to exit.
:q!
Exit Vim without saving changes.
:wq
Write the file and exit.
:x
Almost the same as :wq, write the file and exit if you've made changes to the file. If you haven't made any changes to the file, Vim exits without writing the file.
Moving around in the file
These Vim commands and keys work both in command mode and visual mode.
Vim command
Action
j or Up Arrow
Move the cursor up one line.
k or Down Arrow
Down one line.
h or Left Arrow
Left one character.
l or Right Arrow
Right one character.
e
To the end of a word.
E
To the end of a whitespace-delimited word.
b
To the beginning of a word.
B
To the beginning of a whitespace-delimited word.
0
To the beginning of a line.
^
To the first non-whitespace character of a line.
$
To the end of a line.
H
To the first line of the screen.
M
To the middle line of the screen.
L
To the the last line of the screen.
:n
Jump to line number n. For example, to jump to line 42, you'd type :42
Inserting and overwriting text
Vim command
Action
i
Insert before cursor.
I
Insert to the start of the current line.
a
Append after cursor.
A
Append to the end of the current line.
o
Open a new line below and insert.
O
Open a new line above and insert.
C
Change the rest of the current line.
r
Overwrite one character. After overwriting the single character, go back to command mode.
R
Enter insert mode but replace characters rather than inserting.
The ESC key
Exit insert/overwrite mode and go back to command mode.
Deleting text
Vim command
Action
x
Delete characters under the cursor.
X
Delete characters before the cursor.
dd or :d
Delete the current line.
Entering visual mode
Vim command
Action
v
Start highlighting characters. Use the normal movement keys and commands to select text for highlighting.
V
Start highlighting lines.
The ESC key
Exit visual mode and return to command mode.
Editing blocks of text
Note: the Vim commands marked with (V) work in visual mode, when you've selected some text. The other commands work in the command mode, when you haven't selected any text.
Vim command
Action
~
Change the case of characters. This works both in visual and command mode. In visual mode, change the case of highlighted characters. In command mode, change the case of the character uder cursor.
> (V)
Shift right (indent).
< (V)
Shift left (de-indent).
c (V)
Change the highlighted text.
y (V)
Yank the highlighted text. In Windows terms, "copy the selected text to clipboard."
d (V)
Delete the highlighted text. In Windows terms, "cut the selected text to clipboard."
yy or :y or Y
Yank the current line. You don't need to highlight it first.
dd or :d
Delete the current line. Again, you don't need to highlight it first.
p
Put the text you yanked or deleted. In Windows terms, "paste the contents of the clipboard". Put characters after the cursor. Put lines below the current line.
P
Put characters before the cursor. Put lines above the current line.
Undo and redo
Vim command
Action
u
Undo the last action.
U
Undo all the latest changes that were made to the current line.
Ctrl + r
Redo.
Search
Vim command
Action
/pattern
Search the file for pattern.
n
Scan for next search match in the same direction.
N
Scan for next search match but opposite direction.
Replace
Vim command
Action
:rs/foo/bar/a
Substitute foo with bar. r determines the range and a determines the arguments.
The range (r) can be
nothing
Work on current line only.
number
Work on the line whose number you give.
%
The whole file.
Arguments (a) can be
g
Replace all occurrences in the line. Without this, Vim replaces only the first occurrences in each line.
i
Ignore case for the search pattern.
I
Don't ignore case.
Confirm each substitution. You can type y to substitute this match, n to skip this match, a to substitute this and all the remaining matches ("Yes to all"), and q to quit substitution.
Examples
:452s/foo/bar/
Replace the first occurrence of the word foo with bar on line number 452.
:s/foo/bar/g
Replace every occurrence of the word foo with bar on current line.
:%s/foo/bar/g
Replace every occurrence of the word foo with bar in the whole file.
:%s/foo/bar/gi
The same as above, but ignore the case of the pattern you want to substitute. This replaces foo, FOO, Foo, and so on.
:%s/foo/bar/gc
Confirm every substitution.
:%s/foo/bar/c
For each line on the file, replace the first occurrence of foo with bar and confirm every substitution.
A quick and useful command for checking if a server is under ddos:
netstat -an | grep 'tcp\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
Another very important thing to look at is how many active connections your server is currently processing.
netstat -n | grep :80 |wc -l
netstat -n | grep :80 | grep SYN |wc -l
ps -aux|grep -i HTTP|wc -l
Check free ip in the server using the following command
nmap -sP 50.61.247.83/24 -vv
check the port opened in the server using
nmap local host
semanage port -l | grep ssh
semanage can be used for copying the context from one dir to the other as well /home /home1 using fcontext
To Block a certain IP address that on server .Please use following commands
—
route add ipaddress reject
for example route add 192.168.0.168 reject
You can check whether given IP is blocked on server by using following command
route -n |grep IPaddress
You can check the super blocks using the following command.
dump2fs partition grep -i super block
stat file name
deleted files can also be recovered using debugfs:
Command and Description
•
apropos whatis
Show commands pertinent to string. See also threadsafe
•
man -t man | ps2pdf - > man.pdf
make a pdf of a manual page
which command
Show full path name of command
time command
See how long a command takes
•
time cat
Start stopwatch. Ctrl-d to stop. See also sw
•
nice info
Run a low priority command (The "info" reader in this case)
•
renice 19 -p $$
Make shell (script) low priority. Use for non interactive tasks
dir navigation
•
cd -
Go to previous directory
•
cd
Go to $HOME directory
(cd dir && command)
Go to dir, execute command and return to current dir
•
pushd .
Put current dir on stack so you can popd back to it
file searching
•
alias l='ls -l --color=auto'
quick dir listing
•
ls -lrt
List files by date. See also newest and find_mm_yyyy
•
ls /usr/bin | pr -T9 -W$COLUMNS
Print in 9 columns to width of terminal
find -name '*.[ch]' | xargs grep -E 'expr'
Search 'expr' in this dir and below. See also findrepo
find -type f -print0 | xargs -r0 grep -F 'example'
Search all regular files for 'example' in this dir and below
find -maxdepth 1 -type f | xargs grep -F 'example'
Search all regular files for 'example' in this dir
find -maxdepth 1 -type d | while read dir; do echo $dir; echo cmd2; done
Process each item with multiple commands (in while loop)
•
find -type f ! -perm -444
Find files not readable by all (useful for web site)
•
find -type d ! -perm -111
Find dirs not accessible by all (useful for web site)
•
locate -r 'file[^/]*\.txt'
Search cached index for names. This re is like glob *file*.txt
•
look reference
Quickly search (sorted) dictionary for prefix
•
grep --color reference /usr/share/dict/words
Highlight occurances of regular expression in dictionary
archives and compression
gpg -c file
Encrypt file
gpg file.gpg
Decrypt file
tar -c dir/ | bzip2 > dir.tar.bz2
Make compressed archive of dir/
bzip2 -dc dir.tar.bz2 | tar -x
Extract archive (use gzip instead of bzip2 for tar.gz files)
tar -c dir/ | gzip | gpg -c | ssh user@remote 'dd of=dir.tar.gz.gpg'
Make encrypted archive of dir/ on remote machine
find dir/ -name '*.txt' | tar -c --files-from=- | bzip2 > dir_txt.tar.bz2
Make archive of subset of dir/ and below
find dir/ -name '*.txt' | xargs cp -a --target-directory=dir_txt/ --parents
Make copy of subset of dir/ and below
( tar -c /dir/to/copy ) | ( cd /where/to/ && tar -x -p )
Copy (with permissions) copy/ dir to /where/to/ dir
( cd /dir/to/copy && tar -c . ) | ( cd /where/to/ && tar -x -p )
Copy (with permissions) contents of copy/ dir to /where/to/
( tar -c /dir/to/copy ) | ssh -C user@remote 'cd /where/to/ && tar -x -p'
Copy (with permissions) copy/ dir to remote:/where/to/ dir
dd bs=1M if=/dev/sda | gzip | ssh user@remote 'dd of=sda.gz'
Backup harddisk to remote machine
rsync (Network efficient file copier: Use the --dry-run option for testing)
rsync -P rsync://rsync.server.com/path/to/file file
Only get diffs. Do multiple times for troublesome downloads
rsync --bwlimit=1000 fromfile tofile
Locally copy with rate limit. It's like nice for I/O
rsync -az -e ssh --delete ~/public_html/ remote.com:'~/public_html'
Mirror web site (using compression and encryption)
rsync -auz -e ssh remote:/dir/ . && rsync -auz -e ssh . remote:/dir/
Synchronize current directory with remote one
ssh (Secure SHell)
ssh $USER@$HOST command
Run command on $HOST as $USER (default command=shell)
•
ssh -f -Y $USER@$HOSTNAME xeyes
Run GUI command on $HOSTNAME as $USER
scp -p -r $USER@$HOST: file dir/
Copy with permissions to $USER's home directory on $HOST
ssh -g -L 8080:localhost:80 root@$HOST
Forward connections to $HOSTNAME:8080 out to $HOST:80
ssh -R 1434:imap:143 root@$HOST
Forward connections from $HOST:1434 in to imap:143
wget (multi purpose download tool)
•
(cd dir/ && wget -nd -pHEKk http://www.pixelbeat.org/cmdline.html)
Store local browsable version of a page to the current dir
wget -c http://www.example.com/large.file
Continue downloading a partially downloaded file
wget -r -nd -np -l1 -A '*.jpg' http://www.example.com/dir/
Download a set of files to the current directory
wget ftp://remote/file[1-9].iso/
FTP supports globbing directly
•
wget -q -O- http://www.pixelbeat.org/timeline.html | grep 'a href' | head
Process output directly
echo 'wget url' | at 01:00
Download url at 1AM to current dir
wget --limit-rate=20k url
Do a low priority download (limit to 20KB/s in this case)
wget -nv --spider --force-html -i bookmarks.html
Check links in a file
wget --mirror http://www.example.com/
Efficiently update a local copy of a site (handy from cron)
networking (Note ifconfig, route, mii-tool, nslookup commands are obsolete)
ethtool eth0
Show status of ethernet interface eth0
ethtool --change eth0 autoneg off speed 100 duplex full
Manually set ethernet interface speed
iwconfig eth1
Show status of wireless interface eth1
iwconfig eth1 rate 1Mb/s fixed
Manually set wireless interface speed
•
iwlist scan
List wireless networks in range
•
ip link show
List network interfaces
ip link set dev eth0 name wan
Rename interface eth0 to wan
i
p link set dev eth0 up
Bring interface eth0 up (or down)
•
ip addr show
List addresses for interfaces
ip addr add 1.2.3.4/24 brd + dev eth0
Add (or del) ip and mask (255.255.255.0)
•
ip route show
List routing table
ip route add default via 1.2.3.254
Set default gateway to 1.2.3.254
•
tc qdisc add dev lo root handle 1:0 netem delay 20msec
Add 20ms latency to loopback device (for testing)
•
tc qdisc del dev lo root
Remove latency added above
•
host pixelbeat.org
Lookup DNS ip address for name or vice versa
•
hostname -i
Lookup local ip address (equivalent to host `hostname`)
•
whois pixelbeat.org
Lookup whois info for hostname or ip address
•
netstat -tupl
List internet services on a system
•
netstat -tup
List active connections to/from system
windows networking (Note samba is the package that provides all this windows specific networking support)
•
smbtree
Find windows machines. See also findsmb
nmblookup -A 1.2.3.4
Find the windows (netbios) name associated with ip address
smbclient -L windows_box
List shares on windows machine or samba server
mount -t smbfs -o fmask=666,guest //windows_box/share /mnt/share
Mount a windows share
echo 'message' | smbclient -M windows_box
Send popup to windows machine (off by default in XP sp2)
text manipulation (Note sed uses stdin and stdout. Newer versions support inplace editing with the -i option)
sed 's/string1/string2/g'
Replace string1 with string2
sed 's/\(.*\)1/\12/g'
Modify anystring1 to anystring2
sed '/ *#/d; /^ *$/d'
Remove comments and blank lines
sed ':a; /\\$/N; s/\\\n//; ta'
Concatenate lines with trailing \
sed 's/[ \t]*$//'
Remove trailing spaces from lines
sed 's/\([`"$\]\)/\\\1/g'
Escape shell metacharacters active within double quotes
•
seq 10 | sed "s/^/ /; s/ *\(.\{7,\}\)/\1/"
Right align numbers
sed -n '1000{p;q}'
Print 1000th line
sed -n '10,20p;20q'
Print lines 10 to 20
sed -n 's/.*<title>\(.*\)<\/title>.*/\1/ip;T;q'
Extract title from HTML web page
sed -i 42d ~/.ssh/known_hosts
Delete a particular line
sort -t. -k1,1n -k2,2n -k3,3n -k4,4n
Sort IPV4 ip addresses
•
echo 'Test' | tr '[:lower:]' '[:upper:]'
Case conversion
•
tr -dc '[:print:]' < /dev/urandom
Filter non printable characters
•
history | wc -l
Count lines
set operations (Note you can export LANG=C for speed. Also these assume no duplicate lines within a file)
sort file1 file2 | uniq
Union of unsorted files
sort file1 file2 | uniq -d
Intersection of unsorted files
sort file1 file1 file2 | uniq -u
Difference of unsorted files
sort file1 file2 | uniq -u
Symmetric Difference of unsorted files
join -t'\0' -a1 -a2 file1 file2
Union of sorted files
join -t'\0' file1 file2
Intersection of sorted files
join -t'\0' -v2 file1 file2
Difference of sorted files
join -t'\0' -v1 -v2 file1 file2
Symmetric Difference of sorted files
math
•
echo '(1 + sqrt(5))/2' | bc -l
Quick math (Calculate φ). See also bc
•
echo 'pad=20; min=64; (100*10^6)/((pad+min)*8)' | bc
More complex (int) e.g. This shows max FastE packet rate
•
echo 'pad=20; min=64; print (100E6)/((pad+min)*8)' | python
Python handles scientific notation
•
echo 'pad=20; plot [64:1518] (100*10**6)/((pad+x)*8)' | gnuplot -persist
Plot FastE packet rate vs packet size
•
echo 'obase=16; ibase=10; 64206' | bc
Base conversion (decimal to hexadecimal)
•
echo $((0x2dec))
Base conversion (hex to dec) ((shell arithmetic expansion))
•
units -t '100m/9.58s' 'miles/hour'
Unit conversion (metric to imperial)
•
units -t '500GB' 'GiB'
Unit conversion (SI to IEC prefixes)
•
units -t '1 googol'
Definition lookup
•
seq 100 | (tr '\n' +; echo 0) | bc
Add a column of numbers. See also add and funcpy
calendar
•
cal -3
Display a calendar
•
cal 9 1752
Display a calendar for a particular month year
•
date -d fri
What date is it this friday. See also day
•
[ $(date -d "tomorrow" +%d) = "01" ] || exit
exit a script unless it's the last day of the month
•
date --date='25 Dec' +%A
What day does xmas fall on, this year
•
date --date='@2147483647'
Convert seconds since the epoch (1970-01-01 UTC) to date
•
TZ='America/Los_Angeles' date
What time is it on west coast of US (use tzselect to find TZ)
•
date --date='TZ="America/Los_Angeles" 09:00 next Fri'
What's the local time for 9AM next Friday on west coast US
echo "mail -s 'get the train' P@draigBrady.com < /dev/null" | at 17:45
Email reminder
•
echo "DISPLAY=$DISPLAY xmessage cooker" | at "NOW + 30 minutes"
Popup reminder
locales
•
printf "%'d\n" 1234
Print number with thousands grouping appropriate to locale
•
BLOCK_SIZE=\'1 ls -l
get ls to do thousands grouping appropriate to locale
•
echo "I live in `locale territory`"
Extract info from locale database
•
LANG=en_IE.utf8 locale int_prefix
Lookup locale info for specific country. See also ccodes
•
locale | cut -d= -f1 | xargs locale -kc | less
List fields available in locale database
recode (Obsoletes iconv, dos2unix, unix2dos)
•
recode -l | less
Show available conversions (aliases on each line)
recode windows-1252.. file_to_change.txt
Windows "ansi" to local charset (auto does CRLF conversion)
recode utf-8/CRLF.. file_to_change.txt
Windows utf8 to local charset
recode iso-8859-15..utf8 file_to_change.txt
Latin9 (western europe) to utf8
recode ../b64 < file.txt > file.b64
Base64 encode
recode /qp.. < file.qp > file.txt
Quoted printable decode
recode ..HTML < file.txt > file.html
Text to HTML
•
recode -lf windows-1252 | grep euro
Lookup table of characters
•
echo -n 0x80 | recode latin-9/x1..dump
Show what a code represents in latin-9 charmap
•
echo -n 0x20AC | recode ucs-2/x2..latin-9/x
Show latin-9 encoding
•
echo -n 0x20AC | recode ucs-2/x2..utf-8/x
Show utf-8 encoding
CDs
gzip < /dev/cdrom > cdrom.iso.gz
Save copy of data cdrom
mkisofs -V LABEL -r dir | gzip > cdrom.iso.gz
Create cdrom image from contents of dir
mount -o loop cdrom.iso /mnt/dir
Mount the cdrom image at /mnt/dir (read only)
cdrecord -v dev=/dev/cdrom blank=fast
Clear a CDRW
gzip -dc cdrom.iso.gz | cdrecord -v dev=/dev/cdrom -
Burn cdrom image (use dev=ATAPI -scanbus to confirm dev)
cdparanoia -B
Rip audio tracks from CD to wav files in current dir
cdrecord -v dev=/dev/cdrom -audio -pad *.wav
Make audio CD from all wavs in current dir (see also cdrdao)
oggenc --tracknum='track' track.cdda.wav -o 'track.ogg'
Make ogg file from wav file
disk space (See also FSlint)
•
ls -lSr
Show files by size, biggest last
•
du -s * | sort -k1,1rn | head
Show top disk users in current dir. See also dutop
•
df -h
Show free space on mounted filesystems
•
df -i
Show free inodes on mounted filesystems
•
fdisk -l
Show disks partitions sizes and types (run as root)
•
rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1n
List all packages by installed size (Bytes) on rpm distros
•
dpkg-query -W -f='${Installed-Size;10}\t${Package}\n' | sort -k1,1n
List all packages by installed size (KBytes) on deb distros
•
dd bs=1 seek=2TB if=/dev/null of=ext3.test
Create a large test file (taking no space). See also truncate
•
> file
truncate data of file or create an empty file
monitoring/debugging
•
tail -f /var/log/messages
Monitor messages in a log file
•
strace -c ls >/dev/null
Summarise/profile system calls made by command
•
strace -f -e open ls >/dev/null
List system calls made by command
•
ltrace -f -e getenv ls >/dev/null
List library calls made by command
•
lsof -p $$
List paths that process id has open
•
lsof ~
List processes that have specified path open
•
tcpdump not port 22
Show network traffic except ssh. See also tcpdump_not_me
•
ps -e -o pid,args --forest
List processes in a hierarchy
•
ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed '/^ 0.0 /d'
List processes by % cpu usage
•
ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS
List processes by mem (KB) usage. See also ps_mem.py
•
ps -C firefox-bin -L -o pid,tid,pcpu,state
List all threads for a particular process
•
ps -p 1,2
List info for particular process IDs
•
last reboot
Show system reboot history
•
free -m
Show amount of (remaining) RAM (-m displays in MB)
•
watch -n.1 'cat /proc/interrupts'
Watch changeable data continuously
system information (see also sysinfo) ('#' means root access is required)
•
uname -a
Show kernel version and system architecture
•
head -n1 /etc/issue
Show name and version of distribution
•
cat /proc/partitions
Show all partitions registered on the system
•
grep MemTotal /proc/meminfo
Show RAM total seen by the system
•
grep "model name" /proc/cpuinfo
Show CPU(s) info
•
lspci -tv
Show PCI info
•
lsusb -tv
Show USB info
•
mount | column -t
List mounted filesystems on the system (and align output)
•
grep -F capacity: /proc/acpi/battery/BAT0/info
Show state of cells in laptop battery
#
dmidecode -q | less
Display SMBIOS/DMI information
#
smartctl -A /dev/sda | grep Power_On_Hours
How long has this disk (system) been powered on in total
#
hdparm -i /dev/sda
Show info about disk sda
#
hdparm -tT /dev/sda
Do a read speed test on disk sda
#
badblocks -s /dev/sda
Test for unreadable blocks on disk sda
interactive (see also linux keyboard shortcuts)
•
readline
Line editor used by bash, python, bc, gnuplot, ...
•
screen
Virtual terminals with detach capability, ...
•
mc
Powerful file manager that can browse rpm, tar, ftp, ssh, ...
•
gnuplot
Interactive/scriptable graphing
•
links
Web browser
•
xdg-open .
open a file or url with the registered desktop application
miscellaneous
•
alias hd='od -Ax -tx1z -v'
Handy hexdump. (usage e.g.: • hd /proc/self/cmdline | less)
•
alias realpath='readlink -f'
Canonicalize path. (usage e.g.: • realpath ~/../$USER)
•
set | grep $USER
Search current environment
touch -c -t 0304050607 file
Set file timestamp (YYMMDDhhmm)
•
python -m SimpleHTTPServer
Serve current directory tree at http://$HOSTNAME:8000/
< The list of Vim commands >
Working with files
Vim command
Action
:e filename
Open a new file. You can use the Tab key for automatic file name completion, just like at the shell command prompt.
:w filename
Save changes to a file. If you don't specify a file name, Vim saves as the file name you were editing. For saving the file under a different name, specify the file name.
:q
Quit Vim. If you have unsaved changes, Vim refuses to exit.
:q!
Exit Vim without saving changes.
:wq
Write the file and exit.
:x
Almost the same as :wq, write the file and exit if you've made changes to the file. If you haven't made any changes to the file, Vim exits without writing the file.
Moving around in the file
These Vim commands and keys work both in command mode and visual mode.
Vim command
Action
j or Up Arrow
Move the cursor up one line.
k or Down Arrow
Down one line.
h or Left Arrow
Left one character.
l or Right Arrow
Right one character.
e
To the end of a word.
E
To the end of a whitespace-delimited word.
b
To the beginning of a word.
B
To the beginning of a whitespace-delimited word.
0
To the beginning of a line.
^
To the first non-whitespace character of a line.
$
To the end of a line.
H
To the first line of the screen.
M
To the middle line of the screen.
L
To the the last line of the screen.
:n
Jump to line number n. For example, to jump to line 42, you'd type :42
Inserting and overwriting text
Vim command
Action
i
Insert before cursor.
I
Insert to the start of the current line.
a
Append after cursor.
A
Append to the end of the current line.
o
Open a new line below and insert.
O
Open a new line above and insert.
C
Change the rest of the current line.
r
Overwrite one character. After overwriting the single character, go back to command mode.
R
Enter insert mode but replace characters rather than inserting.
The ESC key
Exit insert/overwrite mode and go back to command mode.
Deleting text
Vim command
Action
x
Delete characters under the cursor.
X
Delete characters before the cursor.
dd or :d
Delete the current line.
Entering visual mode
Vim command
Action
v
Start highlighting characters. Use the normal movement keys and commands to select text for highlighting.
V
Start highlighting lines.
The ESC key
Exit visual mode and return to command mode.
Editing blocks of text
Note: the Vim commands marked with (V) work in visual mode, when you've selected some text. The other commands work in the command mode, when you haven't selected any text.
Vim command
Action
~
Change the case of characters. This works both in visual and command mode. In visual mode, change the case of highlighted characters. In command mode, change the case of the character uder cursor.
> (V)
Shift right (indent).
< (V)
Shift left (de-indent).
c (V)
Change the highlighted text.
y (V)
Yank the highlighted text. In Windows terms, "copy the selected text to clipboard."
d (V)
Delete the highlighted text. In Windows terms, "cut the selected text to clipboard."
yy or :y or Y
Yank the current line. You don't need to highlight it first.
dd or :d
Delete the current line. Again, you don't need to highlight it first.
p
Put the text you yanked or deleted. In Windows terms, "paste the contents of the clipboard". Put characters after the cursor. Put lines below the current line.
P
Put characters before the cursor. Put lines above the current line.
Undo and redo
Vim command
Action
u
Undo the last action.
U
Undo all the latest changes that were made to the current line.
Ctrl + r
Redo.
Search
Vim command
Action
/pattern
Search the file for pattern.
n
Scan for next search match in the same direction.
N
Scan for next search match but opposite direction.
Replace
Vim command
Action
:rs/foo/bar/a
Substitute foo with bar. r determines the range and a determines the arguments.
The range (r) can be
nothing
Work on current line only.
number
Work on the line whose number you give.
%
The whole file.
Arguments (a) can be
g
Replace all occurrences in the line. Without this, Vim replaces only the first occurrences in each line.
i
Ignore case for the search pattern.
I
Don't ignore case.
Confirm each substitution. You can type y to substitute this match, n to skip this match, a to substitute this and all the remaining matches ("Yes to all"), and q to quit substitution.
Examples
:452s/foo/bar/
Replace the first occurrence of the word foo with bar on line number 452.
:s/foo/bar/g
Replace every occurrence of the word foo with bar on current line.
:%s/foo/bar/g
Replace every occurrence of the word foo with bar in the whole file.
:%s/foo/bar/gi
The same as above, but ignore the case of the pattern you want to substitute. This replaces foo, FOO, Foo, and so on.
:%s/foo/bar/gc
Confirm every substitution.
:%s/foo/bar/c
For each line on the file, replace the first occurrence of foo with bar and confirm every substitution.
A quick and useful command for checking if a server is under ddos:
netstat -an | grep 'tcp\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
Another very important thing to look at is how many active connections your server is currently processing.
netstat -n | grep :80 |wc -l
netstat -n | grep :80 | grep SYN |wc -l
ps -aux|grep -i HTTP|wc -l
Check free ip in the server using the following command
nmap -sP 50.61.247.83/24 -vv
check the port opened in the server using
nmap local host
semanage port -l | grep ssh
semanage can be used for copying the context from one dir to the other as well /home /home1 using fcontext
To Block a certain IP address that on server .Please use following commands
—
route add ipaddress reject
for example route add 192.168.0.168 reject
You can check whether given IP is blocked on server by using following command
route -n |grep IPaddress
You can check the super blocks using the following command.
dump2fs partition grep -i super block
stat file name
deleted files can also be recovered using debugfs:
