Unix

Learn a lot of Unix commands with ease here: http://www.grymoire.com/Unix

#

# Download Ubuntu organization file from here: here

# important commands

# command to know if the machine is 32bit or 64bit

file /sbin/init

# display contents of directory (both files and folder) with size and sort by size

du -sh * | sort -n

# trick to remove block comment (uncomment multiple lines) in bash script in vi editor

Press <ESC> and then do the following -- the following command will remove '#' from the beginning (^) of every line from line number 5 to 10.

:5,10s/^#//

# trick to give block comment (comment out multiple lines) in bash script in vi editor

Press <ESC> and then do the following -- the following command will add '#' to the beginning (^) of every line from line number 5 to 10.

:5,10s/^/#/

# trick to remove block comment (uncomment multiple lines) in bash script in vi editor

Press <ESC> and then do the following -- the following command will remove '#' from the beginning (^) of every line from line number 5 to 10.

:5,10s/^#//

# command to know if the RAM is DDR2 or DDR3

sudo dmidecode -t memory

sudo lshw -short -C memory

# you can also install 'hardware lister' in ubuntu that gives a gui, and run it via 'lshw-gtk' command

# command to get the disk usage

df -h

# command to get the file / folder size

# The Linux "du" (Disk Usage) is a standard Unix/Linux command, used to check the information

# of disk usage of files and directories on a machine. The "du" command has many parameter options

# that can be used to get the results in many formats. The "du" command also displays the files

# and directory sizes in a recursively manner.

#

# Using "-h" option with "du" command provides results in "Human Readable Format".

# Means you can see sizes in Bytes, Kilobytes, Megabytes, Gigabytes etc.

# To get the summary of a grand total disk usage size of an directory use the option "-s"

# Using "-a" flag with "du" command displays the disk usage of all the files and directories

du -sh

# command to check any resource exists (file / folder / symlink etc)

# possible options:

# -b filename :: Block special file

# -c filename :: Special character file

# -d directoryname :: Check for directory Existence

# -e filename :: Check for file existence, regardless of type (node, directory, socket, etc.)

# -f filename :: Check for regular file existence not a directory

# -G filename :: Check if file exists and is owned by effective group ID

# -G filename set-group-id :: True if file exists and is set-group-id

# -k filename :: Sticky bit

# -L filename :: Symbolic link

# -O filename :: True if file exists and is owned by the effective user id

# -r filename :: Check if file is a readable

# -S filename :: Check if file is socket

# -s filename :: Check if file is nonzero size

# -u filename :: Check if file set-user-id bit is set

# -w filename :: Check if file is writable

# -x filename :: Check if file is executable

if [ -e "$file" ]; then

    echo "File exists"

else

    echo "File does not exist"

fi

# command to check if a port is used by any process

netstat -nlp | grep 6080

lsof -ti:6080

# command to kill if any process is running on a port

kill -9 $(lsof -ti:6080)

netstat -nlp | grep 6080 | awk '{print ($7)}' | sed 's/\/.*//' | xargs kill -9

# command to kill if any process is running by a given name / pattern

ps -aef | grep src/server.ts | awk '{print $2}' | xargs kill -9

# command to change case of text to lower

echo "HELLO" | awk '{print tolower($0)}'

echo "HELLO" | tr '[:upper:]' '[:lower:]'

TXT="HELLO" && echo "${TXT,,}"

# command to change case of text to upper

echo "hello" | awk '{print toupper($0)}'

echo "hello" | tr '[:lower:]' '[:upper:]'

# command to check host-name and ip of a machine

host `hostname`

# commands to get external / public ip of a machine

curl ifconfig.me

curl ifconfig.me/all.json

curl -s http://checkip.dyndns.org/ | sed 's/[a-zA-Z<>/ :]//g'

dig -4 TXT +short o-o.myaddr.l.google.com @ns1.google.com

curl checkip.amazonaws.com

curl icanhazip.com

curl https://api.ipify.org

curl -4 ip.sb

# python code to get internal ip of a machine

import socket

def extract_ip():

    st = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    try:       

        st.connect(('10.255.255.255', 1))

        IP = st.getsockname()[0]

    except Exception:

        IP = '127.0.0.1'

    finally:

        st.close()

    return IP

print(extract_ip())

# command to search text in files in a given directory

grep -inr "Text" folder/to/be/searched/

# command replace substring with another value in a string.

# "sed" command can be used for this purpose, the format of "sed" command is: sed 's/<text to be replaced>/<replacement text>/'

# "sed" command can also be used to replace texts in a file.

# The follwoing command replaces ":def" with ":xyz" and prints "abc:xyz" on screen (notice the usage of regex and how we piped the output to the next command).

echo abc:def | sed 's/:.*/:xyz/'

# More about "sed" command is here: http://www.grymoire.com/Unix/Sed.html

# the following command shows a good example of getting the id of the

# JAVA process that is using the port 10981, and then killing the process

# (notice the usage of escape '\' to feed special character '/' as input to "sed" command).

netstat -nlp | grep 10981 | awk '{print ($7)}' | sed 's/\/.*//' | xargs kill -9

# 'awk' is a very powerful command.

# The following command shows how to read the latest file from the current directory.

# ('NF' signifies the number of columns in a line)

ls -ltr | awk '{print $NF}' | tail -n 1 | xargs less

# Another way to read the latest file without 'awk'

ls -t1 | head -1 | xargs less

# way to run any process at background

nohup ./the_process_script.sh &

# extract last 100 lines from a file, and more from "tail" command

tail -100 filename

tail -f filename : display grows as the original file grows in real-time

# use "2>/dev/null" to channelize output to NULL device (nowhere)

# > file redirects stdout to file

# 1> file redirects stdout to file

# 2> file redirects stderr to file

# &> file redirects stdout and stderr to file

# nohup ./qpid-server > /dev/null 2>&1 & redirects stdout and stderr to NULL device and also returns back to command shell

du -sh * 2>/dev/null

# command to compress file / folder using zip / unzip (-e is to make password-protected zip)

zip -r filename.zip folder_to_zip_recursively

zip -er filename.zip folder_to_zip_recursively

unzip filename.zip

# command to compress file / folder using tar

tar -zcvf filename.tar.gz folder_to_zip_recursively/

tar -zxvf filename.tar.gz

# command to change mode of directory contents recursively after entering the directory

chmod 777 -R .

# command to find selective processes and kill them

ps -aef | grep domainA5 | awk '{print ($2)}' | xargs kill -9

# command to find selective files / folders and delete them

find . -name '*server1.lok' | xargs rm -rvf

# command to find count of lines where a text occurred in a file, and other good uses of "wc" command

cat thefile.txt | grep "Text to find" | wc -l

wc -l : Prints the number of lines in a file.

wc -w : prints the number of words in a file.

wc -c : Displays the count of bytes in a file.

wc -m : prints the count of characters from a file.

wc -L : prints only the length of the longest line in a file.

# command to copy / transfer files from one remote unix machine to another remote unix machine

scp FILE*.TXT u121212@remoteserver.ny.net:/apps/target

# command to change command prompt

set "PS1='$PWD #'" in "vi /home/calcadm/.bashrc" file to change command prompt

# use echo -e to print new line character

echo -e "\n\t..."

# Codes for symbols -- Search unicodes for symbol here: https://www.compart.com/en/unicode/

printf '\n  \xF0\x9F\x8F\x83 \t This is Runner'

printf '\n  \xF0\x9F\x8D\xBA  \t This is Beer Mug'

printf '\n  \xF0\x9F\x8D\xBB  \t This is Clinking Beer Mugs'

printf '\n  \xE2\x9B\x94  \t This is Failure Sign'

printf '\n  \xF0\x9F\x92\x83  \t This is Dancer'

printf '\n  \xE2\x9C\x8B  \t This is Raised Hand'

printf '\n  \xF0\x9F\x9A\x97  \t This is Car (side)'

printf '\n  \xF0\x9F\x9A\x98  \t This is Car (front)'

printf '\n  \xF0\x9F\x9B\xBA  \t This is Auto Rickshaw'

printf '\n  \xF0\x9F\x9A\xA2  \t This is Ship'

printf '\n  \xF0\x9F\x9B\xA9  \t This is Airplane'

printf '\n  \xF0\x9F\x9A\x80  \t This is Rocket'

printf '\n  \xF0\x9F\x91\x80  \t This is Eyes'

printf '\n  \xF0\x9F\x91\x81  \t This is Eye'

printf '\n  \xF0\x9F\x91\x93  \t This is Eyeglasses'

printf '\n  \xF0\x9F\x98\x8A  \t This is Smily'

printf '\n  \xF0\x9F\xA5\xBA  \t This is Sad Face'

printf '\n  \xF0\x9F\x98\xA2  \t This is Crying Face'

printf '\n  \xF0\x9F\xA4\xA3  \t This is ROFL'

printf '\n  \xF0\x9F\x93\x9C  \t This is Scroll'

printf '\n  \xF0\x9F\x9B\x92  \t This is Shopping Cart'

printf '\n  \xF0\x9F\x94\xA5  \t This is Fire'

printf '\n  \xF0\x9F\xA7\xA8  \t This is Firecracker'

printf '\n  \xF0\x9F\x92\xA3  \t This is Bomb'

printf '\n  \xF0\x9F\x8C\xBB  \t This is Sunflower'

printf '\n  \xF0\x9F\x8D\xB2  \t This is Food'

printf '\n  \xF0\x9F\x8F\xA0  \t This is House'

printf '\n  \xF0\x9F\x8F\xA2  \t This is Office'

printf '\n  \xF0\x9F\x93\x9E  \t This is Telephone'

printf '\n  \xF0\x9F\x93\xB1  \t This is Mobile phone'

printf '\n  \xF0\x9F\x92\xBB  \t This is Laptop / Computer'

printf '\n  \xF0\x9F\x92\xB0  \t This is Money'

printf '\n  \xF0\x9F\x8E\xB2  \t This is Dice'

printf '\n  \xF0\x9F\x92\xA1  \t This is a Electric Bulb'

printf '\n  \xF0\x9F\x8D\xB0  \t This is a Cake'

printf '\n  \xF0\x9F\x8E\x82  \t This is a Birthday Cake'

printf '\n  \xF0\x9F\x92\xA4  \t This is a Sleeping Symbol'

printf '\n  \xE2\x8F\xB1  \t This is a Stop Watch'

printf '\n  \xE2\x8F\xB0  \t This is a Alarm Clock'

printf '\n  \xF0\x9F\x9A\xA9  \t This is a Flag'

printf '\n  \xE2\x9D\x8C  \t This is a Negative Red Cross'

printf '\n  \xF0\x9F\x94\xA8  \t This is a Hammer'

printf '\n  \xF0\x9F\x9B\xA0 \t This is a Hammer and Wrench'

printf '\n  \xF0\x9F\x90\x8D \t This is a Snake'

printf '\n  \xF0\x9F\x91\x87 \t This is Finger Down'

printf '\n  \xF0\x9F\x96\x90 \t This is Hi Five'

printf '\n  \xF0\x9F\xA4\x9E \t This is Crossed Finger'

printf '\n  \xF0\x9F\xA4\xAB \t This is Hush Up'

printf '\n  \xF0\x9F\x91\x8D \t This is Thumbs Up'

printf '\n  \xF0\x9F\x91\x8E \t This is Thumbs Down'

printf '\n  \xF0\x9F\x94\x94 \t This is Bell'

printf '\n  \xF0\x9F\x94\x95 \t This is No-Bell / No-ring / Silence'

printf '\n  \xF0\x9F\xA7\xB9 \t This is Broom'

printf '\n  \xF0\x9F\x8E\x89 \t This is Party'

printf '\n  \xF0\x9F\x93\x94 \t This is Notebook'

printf '\n  \xF0\x9F\x93\x96 \t This is Book'

printf '\n  \xF0\x9F\x93\x9A \t This is Books'

printf '\n  \xF0\x9F\x94\x96 \t This is Bookmark'

printf '\n  \xF0\x9F\x93\x82 \t This is File / Folder'

printf '\n  \xF0\x9F\x96\x8B \t This is Pen'

printf '\n  \xF0\x9F\x94\x92 \t This is Closed Lock'

printf '\n  \xF0\x9F\x94\x93 \t This is Opened Lock'

printf '\n  \xF0\x9F\x94\x90 \t This is Lock with Key'

printf '\n  \xF0\x9F\x9B\x91 \t This is Stop Sign'

# write a function in bash in single line / inline

# notice: how a ';' is to be added before closing '}'

print_message() { printf "\n \xF0\x9F\x9A\xA9  ${1}\n\n"; }

# convert DOS to UNIX file format

# PERL one liner (s/ for 'regex replacement', and /g for 'replace-all' or 'global-replace')

perl -pi -e 's/\r\n/\n/g' *.*

# 2 possible ways to find full path of currently executing script and its parent folder

# ${BASH_SOURCE[0]} (or, more simply, $BASH_SOURCE[1] ) contains the (potentially relative)

# path of the containing script in all invocation scenarios, notably also when the

# script is sourced, which is not true for "$0" -- thus prefer BASH_SOURCE[0] over "$0"

SCRIPT_PATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" > /dev/null 2>&1; pwd -P)"

SCRIPT_PATH="$(cd "$(dirname "$0")" > /dev/null 2>&1; pwd -P)"

ROOT=$(dirname "$SCRIPT_PATH")

echo "Current script's path: "$SCRIPT_PATH

echo "Root path is: "$ROOT

# use $# to check the number of inputs, and $* to see list of inputs

#!/bin/sh

if [ $# -eq 0 ]

then

    echo -e "\nNo input given.."

    exit 1

else

    echo -e "\nInputs given: "$#

    echo -e "\nInputs are: "$*

    COUNT=1;

    for ip in $*

    do

        echo -e "\nInput_"$COUNT": "$ip

        COUNT=$((COUNT+1))

    done

    # use '`' character to evaluate expression / command

    NUM=0;

    NUM=$((NUM+`cat abc.txt | grep "^A\^B" | wc -l`))

    echo "Number of lines in abc.txt file that starts with string 'A^B' is: "$NUM

fi

# for loop example

#!/bin/sh

COUNTER=0

while [ $COUNTER -lt 10 ];

do

    echo The counter is $COUNTER

    let COUNTER=COUNTER+1

done

# another example

# working with input as files

#!/bin/sh

for file in $*

do

    # read the file row by row

    while read row

    do

        # use regex to chek if row starts with DEK or DEP

        if [[ $row =~ ^DE(K|P) ]]

        then

            echo -e "\nRow: "$row

        fi

    done < $file

    # the above line shows how to get input stream from file

done

# another example

# working with awk command

#!/bin/sh

line="this,is-a,comma,separated,line"

echo $line | awk -F , '{

    # split "is-a" in two distinct words "is" and "a"

    JOIN=split($2,ARRAY,"-")

    IS=ARRAY[1]

    A=ARRAY[1]

    if(JOIN==2) {

        A=ARRAY[2]

    }

    print "Got the \x27line\x27: "$1" "IS" "A" "$3" "$4" "$5"

}' >> output.txt

# the above line snds output to a text file

# the output will be Got the 'line': this is a comma separated line

# notice how we used \x27 for single-quote, as awk command's function was already wrapped in single-quote

# another example

# use '`' character to evaluate expression / command

#!/bin/sh

for file in $*

do

    ROW_COUNT=0

    while read row

    do

        ROW_COUNT=$((ROW_COUNT+1))

        if [ `expr $ROW_ROW_COUNT % 500` -eq 0 ]

        then

            echo "Read rows: "$ROW_ROW_COUNT

        fi

    done < $file

done

# array in bash example

#!/bin/sh

COUNTER=0

VALUE=0

echo 'Populate array'

while [ $COUNTER -lt 10 ];

do

    array[$COUNTER]=$VALUE

    let COUNTER=COUNTER+1

    let VALUE=VALUE+1

done

echo 'Array population done'

echo 'The array is: '${array[*]}

# commons script to different types of messages

#!/bin/bash

# call: print_message "hello world"

# prints: "  🚩  hello world"

print_message() {

    printf "\n \xF0\x9F\x9A\xA9  ${1}\n\n"

}

# call: print_error "hello world"

# prints: " ⛔  hello world"

print_error() {

    printf "\n \xE2\x9B\x94  ${1}\n\n"

}

# call: print_start "hello world"

# prints: " 🏃  hello world"

print_start() {

    printf "\n \xF0\x9F\x8F\x83  ${1}\n\n"

}

# call: print_process_triggered "hello world"

# prints: " 🚀  hello world"

print_process_triggered() {

    printf "\n \xF0\x9F\x9A\x80  ${1}\n\n"

}

# call: print_end "hello world"

# prints: " 🍺  hello world"

print_end() {

    printf "\n \xF0\x9F\x8D\xBA  ${1}\n\n"

}

# call: print_alert "hello world"

# prints: " ❌  hello world"

print_alert() {

    printf "\n \xE2\x9D\x8C  ${1}\n\n"

}

# call: print_comment "hello world"

# prints: " 💡  hello world"

print_comment() {

    printf "\n \xF0\x9F\x92\xA1  ${1}\n\n"

}

# call: print_crash "hello world"

# prints: " 🔥  hello world"

print_crash() {

    printf "\n \xF0\x9F\x94\xA5  ${1}\n\n"

}

# call: print_success "hello world"

# prints: " 👍  hello world"

print_success() {

    printf "\n \xF0\x9F\x91\x8D  ${1}\n\n"

}

# call: print_failure "hello world"

# prints: " 👎  hello world"

print_failure() {

    printf "\n \xF0\x9F\x91\x8E  ${1}\n\n"

}

# call: print_notification "hello world"

# prints: " 🔔  hello world"

print_notification() {

    printf "\n \xF0\x9F\x94\x94  ${1}\n\n"

}

# call: print_sleeping "hello world"

# prints: " 💤  hello world"

print_sleeping() {

    printf "\n \xF0\x9F\x92\xA4  ${1}\n\n"

}

# call: print_waiting "hello world"

# prints: " ⏱  hello world"

print_waiting() {

    printf "\n \xE2\x8F\xB1  ${1}\n\n"

}

# call: print_timing "hello world"

# prints: " ⏰  hello world"

print_timing() {

    printf "\n \xE2\x8F\xB0  ${1}\n\n"

}

# call: print_stats "hello world"

# prints: " 📜  hello world"

print_stats() {

    printf "\n \xF0\x9F\x93\x9C  ${1}\n\n"

}

# call: print_instructions "hello world"

# prints: " ✋  hello world"

print_instructions() {

    printf "\n \xE2\x9C\x8B  ${1}\n\n"

}

# call: print_cleanup "hello world"

# prints: " 🧹  hello world"

print_cleanup() {

    printf "\n \xF0\x9F\xA7\xB9  ${1}\n\n"

}

# call: print_celebration "hello world"

# prints: " 🎉  hello world"

print_celebration() {

    printf "\n \xF0\x9F\x8E\x89  ${1}\n\n"

}