Network Linux Commands
Networking Commands for Situations
tail
Print the last N number of data of given input. By default, it will print the last 10 lines of the specified file.
Syntax: tail [OPTION] [FILE]
-n
--lines
tail -n [number] [filename]
Specify number of lines
-c
--bytes
tail -c [+/- number] [FILENAME]
Prints the last 'num' bytes (pos or neg number)
-q
--quiet
tail -q [FILENAME] [FILENAME]
Data from each file is not preceded by its file name.
-v
--verbose
tail -v [FILENAME]
Data from specified file is always preceded by filename.
-f
--follow
tail -f [FILENAME]
Follow live updates to file.
Curl
grep
Grep filter searches a file for a particular pattern of characters, and displays all lines that contain that pattern.
Syntax: grep [OPTION] [pattern] [FILENAME]
-c
Prints count of the lines that match a pattern.
-h
Display the matched lines, do not display the filenames.
-i
Ignores, case for matching.
-l
Displays list of filenames only.
-n
Display the matched lines and line numbers.
-v
Prints out all the lines that don't match the pattern.
-e
Specifies expression with this option (Can be
used multiple times)
-f
Takes patterns from file, one per line.
-E
Treats patten as an extended regular expression.
-w
Match whole word.
-o
Print only the matched parts of a matching line, with each on a seperate output line.
-A n
Prints searched line and n(lines) after the results.
-B n
Prints searched line and n(lines) before the result.
-C n
Prints searched line and n(lines) after before the results.
dig
Finds DNS Information
Syntax: dig [SERVER] [NAME] [TYPE]
+short
Displays short answer option
+noall +answer
To access detailed info on the answers section.
+trace
Displays each different server the query goes through.
-x
Look up using IP Address
cd
Change directory
Syntax: cd [DIRECTORY]
/
Change to the root directory.
~
Change to the home directory.
..
Move to the parent directory.
"dir name" or dir\ name
Navigate to a directory with white spaces.
telnet
call IP address with a specific port
Syntax: telnet [IP Address] [PORT]
cat
Displays file content on output.
Syntax: cat [filename]
wget
Stands for Web Get. It downloads a file from the internet.
wget [OPTION] [URL]
-b
Download in the background.
-o
Overwrite the log while
PWD
Prints current working directory
Syntax: pwd [Options]
-L
Prints logical directory.
-P
Prints actual working directory.
echo
Echo is used to display of line of text/string that is passed as an argument.
Syntax: echo[OPTION] [STRING]
Backslash escapes
\b: removes all spaces
\c: suppress trailing new line
\n: create new line
\t: adds tab
\r: Returns everything after r
\v: add vertical tab
-e
Enables the interpretation of backslash escapes
*
works the same way as ls
-n
used to omit trailing newline
cp
CP stands for copy. Used to copy files or groups of files or directory.
Syntax:
cp [OPTION] [SOURCE] [DESTINATION]
cp [OPTION] [SOURCE] [DIRECTORY]
cp [OPTION][SOURCE1] [SOURCE2]-n [DESTINATION]
-i
Systems first warns user before overwriting the destination file.
-b
This option creates the backup of the destination file in the same folder with a different name and in a different format.
-f
Used if user doesn't have writing permission. It will delete destination file first then copy of content is done from source to destination.
-r or -R
df
check disk space
Syntax: df [option]
-h: human readable format
free -mh
check ram
htop
check cpu
top -c
check cpu (old version)
awk
find specific columns
Syntax: awk '{print __}' [file]
sed
FInd and replace, insertion or deletion. Most common use of sed is find and replace.
Syntax: sed [OPTIONS] [Script] [INPUTFILE]
\1: first occurance
\2: second occurance
\g: global replace
sed 'n s/word1/word2/' [FILE]
netstat
netstat -p IP output: list of all connections for the PHv4 protocol
netstat -s -p icmpv6 output: list all statistics on the ICMPv6 protocol.
netstat -ano output: display all open ports and active connections (numeric and process ID included)
netstat -a | less output: shows all the connected and waiting sockets in a easier way to read
netstat -at | less output: see only the TCP sockets.
netstat -au | less output see only UDP sockets.
netstat -l | less out output: sockets that are in the listening state. (can be combined with -t and -u)
netstat -st | less output: statistics for TCP
netstat -su | less output: statistics for UDP
netstat -r output: routing table
mtr [Domain]
live traceroute
strace -p [PROCESSID]
alias [alias]="[command]"
You can also nano into
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