How to call a shell script from python code?

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This is how to How to call a shell script from python code

To call a shell script from Python code, you can use the subprocess module, which is a part of the Python standard library. The subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes.

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import subprocess

# Call the script using the `call` function
subprocess.call([“/path/to/script.sh”])

# Call the script and pass arguments to it
subprocess.call([“/path/to/script.sh”, “arg1”, “arg2”])

# Call the script and store the output in a variable
output = subprocess.check_output([“/path/to/script.sh”])
print(output)

In this example, the call function is used to execute the shell script and wait for it to complete. The check_output function is used to execute the shell script and store the output in a variable.

You can also use the Popen class from the subprocess module to execute the shell script in a separate process and communicate with it in real-time.

import subprocess subprocess.call(['sh shell_script.sh arguments'])

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import sys, os os.system("sh shell_script.sh arguments")

Output Example

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January 11, 2017February 12, 2019

Basic Gotcha Linux Questions for IT DevOps and SysAdmin Interviews

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Some IT DevOps, SysAdmin, Developer positions require the knowledge of basic linux Operating System. Most of the time, we know the answer but forget them when we don’t practice very often. This refresher will help you prepare for the linux portion of your IT interview by answering some gotcha Linux Questions for IT DevOps and SysAdmin Interviews.

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I- Networking:

How many bytes are there in a MAC address?
48.
MAC, Media Access Control, address is a globally unique identifier assigned to network devices, and therefore it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format.
What are the different parts of a TCP packet?
The term TCP packet appears in both informal and formal usage, whereas in more precise terminology segment refers to the TCP protocol data unit (PDU), datagram to the IP PDU, and frame to the data link layer PDU: … A TCP segment consists of a segment header and a data section.
Networking: Which command is used to initialize an interface, assign IP address, etc.
ifconfig (interface configuration). The equivalent command for Dos is ipconfig.
Other useful networking commands are: Ping, traceroute, netstat, dig, nslookup, route, lsof
What’s the difference between TCP and UDP; Between DNS TCP and UDP?
There are two types of Internet Protocol (IP) traffic. They are TCP or Transmission Control Protocol and UDP or User Datagram Protocol. TCP is connection oriented – once a connection is established, data can be sent bidirectional. UDP is a simpler, connectionless Internet protocol.
The reality is that DNS queries can also use TCP port 53 if UDP port 53 is not accepted.
DNS uses TCP for Zone Transfer over port :53.
DNS uses UDP for DNS Queries over port :53.
What are defaults ports used by http, telnet, ftp, smtp, dns, , snmp, squid?
All those services are part of the Application level of the TCP/IP protocol.
http => 80
telnet => 23
ftp => 20 (data transfer), 21 (Connection established)
smtp => 25
dns => 53
snmp => 161
dhcp => 67 (server), 68 (Client)
ssh => 22
squid => 3128
How many host available in a subnet (Class B and C Networks)
How DNS works?
When you enter a URL into your Web browser, your DNS server uses its resources to resolve the name into the IP address for the appropriate Web server.
What is the difference between class A, class B and class C IP addresses?
Class A Network (/ 8 Prefixes)
This network is 8-bit network prefix. IP address range from 0.0.0.0 to 127.255.255.255
Class B Networks (/16 Prefixes)
This network is 16-bit network prefix. IP address range from 128.0.0.0 to 191.255.255.255Class C Networks (/24 Prefixes)
This network is 24-bit network prefix.IP address range from 192.0.0.0 to 223.255.255.255
Difference between ospf and bgp?
The first reason is that BGP is more scalable than OSPF. , and this, normal igp like ospf cannot perform. Generally speaking OSPF and BGP are routing protocols for two different things. OSPF is an IGP (Interior Gateway Protocol) and is used internally within a companies network to provide routing.

II- Operating System
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How to find the Operating System version?
$uname -a
To check the distribution for redhat for example: $cat /etc/redhat –release
How to list all the process running?
top
To list java processes, ps -ef | grep java
To list processes on a specific port:
netstat -aon | findstr :port_number
lsof -i:80
How to check disk space?
df shows the amount of disk space used and available.
du displays the amount of disk used by the specified files and for each subdirectories.
To drill down and find out which file is filling up a drive: du -ks /drive_name/* | sort -nr | head
How to check memory usage?
free or cat /proc/meminfo
What is the load average?
It is the average sum of the number of process waiting in the queue and the number of process currently executing over the period of 1, 5 and 15 minutes. Use top to find the load average.
What is a load balancer?
A load balancer is a device that acts as a reverse proxy and distributes network or application traffic across a number of servers. Load balancers are used to increase capacity (concurrent users) and reliability of applications.
What is the Linux Kernel?
The Linux Kernel is a low-level systems software whose main role is to manage hardware resources for the user. It is also used to provide an interface for user-level interaction.
What is the default kill signal?
There are many different signals that can be sent (see signal for a full list), although the signals in which users are generally most interested are SIGTERM (“terminate”) and SIGKILL (“kill”). The default signal sent is SIGTERM.
kill 1234
kill -s TERM 1234
kill -TERM 1234
kill -15 1234

Describe Linux boot process
BIOS => MBR => GRUB => KERNEL => INIT => RUN LEVEL
As power comes up, the BIOS (Basic Input/Output System) is given control and executes MBR (Master Boot Record). The MBR executes GRUB (Grand Unified Boot Loader). GRUB executes Kernel. Kernel executes /sbin/init. Init executes run level programs. Run level programs are executed from /etc/rc.d/rc*.d
Mac OS X Boot Process:

Boot ROM	Firmware. Part of Hardware system BootROM firmware is activated
POST	Power-On Self Test initializes some hardware interfaces and verifies that sufficient memory is available and in a good state.
EFI	Extensible Firmware Interface EFI does basic hardware initialization and selects which operating system to use.
BOOTX	boot.efi boot loader load the kernel environment
Rooting/Kernel	The init routine of the kernel is executed boot loader starts the kernel’s initialization procedure Various Mach/BSD data structures are initialized by the kernel. The I/O Kit is initialized. The kernel starts /sbin/mach_init
Run Level	mach_init starts /sbin/init init determines the runlevel, and runs /etc/rc.boot, which sets up the machine enough to run single-user. rc.boot figures out the type of boot (Multi-User, Safe, CD-ROM, Network etc.)

List services enabled at a particular run level
chkconfig –list | grep 5:0n
Enable|Disable a service at a specific run level: chkconfig on|off –level 5
How do you stop a bash fork bomb?
Create a fork bomb by editing limits.conf:
root hard nproc 512
Drop a fork bomb as below:
:(){ :|:& };:
Assuming you have access to shell:
kill -STOP
killall -STOP -u user1
killall -KILL -u user1
What is a fork?
fork is an operation whereby a process creates a copy of itself. It is usually a system call, implemented in the kernel. Fork is the primary (and historically, only) method of process creation on Unix-like operating systems.
What is the D state?
D state code means that process is in uninterruptible sleep, and that may mean different things but it is usually I/O.

III- File System

What is umask?
umask is “User File Creation Mask”, which determines the settings of a mask that controls which file permissions are set for files and directories when they are created.
What is the role of the swap space?
A swap space is a certain amount of space used by Linux to temporarily hold some programs that are running concurrently. This happens when RAM does not have enough memory to hold all programs that are executing.

What is the role of the swap space?
A swap space is a certain amount of space used by Linux to temporarily hold some programs that are running concurrently. This happens when RAM does not have enough memory to hold all programs that are executing.
What is the null device in Linux?
The null device is typically used for disposing of unwanted output streams of a process, or as a convenient empty file for input streams. This is usually done by redirection. The /dev/null device is a special file, not a directory, so one cannot move a whole file or directory into it with the Unix mv command.You might receive the “Bad file descriptor” error message if /dev/null has been deleted or overwritten. You can infer this cause when file system is reported as read-only at the time of booting through error messages, such as“/dev/null: Read-only filesystem” and “dup2: bad file descriptor”.
In Unix and related computer operating systems, a file descriptor (FD, less frequently fildes) is an abstract indicator (handle) used to access a file or other input/output resource, such as a pipe or network socket.
What is a inode?
The inode is a data structure in a Unix-style file system that describes a filesystem object such as a file or a directory. Each inode stores the attributes and disk block location(s) of the object’s data.

IV- Databases

What is the difference between a document store and a relational database?
In a relational database system you must define a schema before adding records to a database. The schema is the structure described in a formal language supported by the database and provides a blueprint for the tables in a database and the relationships between tables of data. Within a table, you need to define constraints in terms of rows and named columns as well as the type of data that can be stored in each column.In contrast, a document-oriented database contains documents, which are records that describe the data in the document, as well as the actual data. Documents can be as complex as you choose; you can use nested data to provide additional sub-categories of information about your object. You can also use one or more document to represent a real-world object.
How to optimise a slow DB?
- Rewrite the queries
- Change indexing strategy
- Change schema
- Use an external cache
- Server tuning and beyond
How would you build a 1 Petabyte storage with commodity hardware?
Using JBODs with large capacity disks with Linux in a distributed storage system stacking nodes until 1PB is reached.
JBOD (which stands for “just a bunch of disks”) generally refers to a collection of hard disks that have not been configured to act as a redundant array of independent disks (RAID) array.

V- Scripting

What is @INC in Perl?
The @INC Array. @INC is a special Perl variable that is the equivalent to the shell’s PATH variable. Whereas PATH contains a list of directories to search for executables, @INC contains a list of directories from which Perl modules and libraries can be loaded.
Strings comparison – operator – for loop – if statement
Sort access log file by http Response Codes
Via Shell using linux commands
cat sample_log.log | cut -d ‘”‘ -f3 | cut -d ‘ ‘ -f2 | sort | uniq -c | sort -rn
Sort access log file by http Response Codes Using awk
awk ‘{print $9}’ sample_log.log | sort | uniq -c | sort -rn
Find broken links from access log file
awk ‘($9 ~ /404/)’ sample_log.log | awk ‘{print $7}’ sample_log.log | sort | uniq -c | sort -rn
Most requested page:
awk -F\” ‘{print $2}’ sample_log.log | awk ‘{print $2}’ | sort | uniq -c | sort -r
Count all occurrences of a word in a file
grep -o “user” sample_log.log | wc -w

Learn more at http://career.guru99.com/top-50-linux-interview-questions/

Real Time Linux Jobs

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July 21, 2016January 3, 2023

Script with hash tables on windows and Linux

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How to declare and write a script with hash tables on windows and linux

A hash table, also known as a hash map, is a data structure that is used to store key-value pairs. It is an efficient way to store data that can be quickly retrieved using a unique key.

Here is an example of how to declare and write a script with a hash table in Python:

# Declare an empty hash table
hash_table = {}

# Add some key-value pairs to the hash table
hash_table[‘key1’] = ‘value1’
hash_table[‘key2’] = ‘value2’
hash_table[‘key3’] = ‘value3’

# Access a value using its key
print(hash_table[‘key2’]) # Output: “value2”

# Modify a value using its key
hash_table[‘key2’] = ‘new value’
print(hash_table[‘key2’]) # Output: “new value”

# Delete a key-value pair using the `del` statement
del hash_table[‘key1’]

# Check if a key is in the hash table using the `in` operator
print(‘key1’ in hash_table) # Output: False

 # Output: False

In this example, we declare an empty hash table using the {} syntax. We then add some key-value pairs to the hash table using the [] syntax. We access a value using its key, modify a value using its key, delete a key-value pair using the del statement, and check if a key is in the hash table using the in operator.

I hope this helps! Let me know if you have any questions.

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- Hash tables with powershell on windows
  Declaration:
  $states=@{“Alberta” = “Calgary”; “British Columbia” = “Vancouver”; “Ontario” = “Toronto” ; “Quebec” = “Montreal”}
  Name
  _____ Value
  _______
  Alberta Calgary
  British Columbia Vancouver
  Ontario Toronto
  Quebec Montreal
  Add new key-value in hashtable:
  $states.Add(“Manitoba”,”Winnipeg”)
  Remove key-value in hashtable:
  $states.Remove(“Manitoba”,”Winnipeg”)
  Change value in hashtable:
  $states.Set_Item(“Ontario”,”Ottawa”)
  Retrieve value in hashtable:
  $states.Get_Item(“Alberta”)
  Find key in hashtable:
  $states.ContainsKey(“Alberta”)
  Find Value in hashtable:
  $states.ContainsValue(“Calgary”)
  Count items in hashtable:
  $states.Count
  Sort items by Name in hashtable:
  $states.GetEnumerator() | Sort-Object Name -descending
  Sort items by Value in hashtable:
  $states.GetEnumerator() | Sort-Object Value -descending
- Hash tables with perl on linux or windows
  Declaration:
  my %hash = (); #Initialize a hash
  my $hash_ref = {}; # Initialize a hash reference. ref will return HASH
  Clear (or empty) a hash
  for (keys %hash)
  {
  delete $hash{$_};
  }
  Clear (or empty) a hash reference
  for (keys %$href)
  {
  delete $href->{$_};
  }
  Add a key/value pair to a hash
  $hash{ ‘key’ } = ‘value’; # hash
  $hash{ $key } = $value; # hash, using variables
  Using Hash Reference
  $href->{ ‘key’ } = ‘value’; # hash ref
  $href->{ $key } = $value; # hash ref, using variables
  Add several key/value pairs to a hash
  %hash = ( ‘key1’, ‘value1’, ‘key2’, ‘value2’, ‘key3’, ‘value3’ );
  %hash = (
  key1 => ‘value1’,
  key2 => ‘value2’,
  key3 => ‘value3’,
  );
  Copy a hash
  my %hash_copy = %hash; # copy a hash
  my $href_copy = $href; # copy a hash ref
  Delete a single key/value pair
  delete $hash{$key};
  delete $hash_ref->{$key};

Hash tables with python on linux or windows

Hash tables are called dictionary in python.
Declaration:
dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}
Accessing Values
print “dict[‘Name’]: “, dict[‘Name’]
print “dict[‘Age’]: “, dict[‘Age’]
Output:
dict[‘Name’]: Zara
dict[‘Age’]: 7
Updating Dictionary
dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}

dict[‘Age’] = 8; # update existing entry
dict[‘School’] = “DPS School”; # Add new entry
Delete Dictionary Elements
#!/usr/bin/python

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dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}

del dict[‘Name’]; # remove entry with key ‘Name’
dict.clear(); # remove all entries in dict
del dict ; # delete entire dictionary

Source:

September 8, 2015January 3, 2023

reverse a string on Linux and Windows

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How to reverse a string on Linux and Windows

On Linux:

Using the rev command: The rev command is a utility that reverses the lines of a file or the characters in a string. To reverse a string, you can use the echo command to pass the string to rev:

echo "string" | rev

Using the sed command: The sed command is a powerful utility that can perform various text transformations. To reverse a string, you can use the sed command with the -r option and the 's/.*(.)/\1/g' expression:

echo "string" | sed -r 's/.*(.)/\1/g'

Using the awk command: The awk command is a programming language that is used for text processing. To reverse a string, you can use the awk command with the {print} action:

echo "string" | awk '{print $1}'

On Windows:

Using the powershell command: The powershell command is a shell that provides a command-line interface for Windows. To reverse a string, you can use the powershell command with the -C option and the '[System.Text.Encoding]::Unicode.GetString([System.Text.Encoding]::Unicode.GetBytes("string"))' expression:

powershell -C "[System.Text.Encoding]::Unicode.GetString([System.Text.Encoding]::Unicode.GetBytes("string"))"

Using the cmd command: The cmd command is the command-line interpreter for Windows. To reverse a string, you can use the cmd command with the for loop:

cmd /c "for /L %i in (1,1,%len%) do @echo !string:~%len%-%i,1!"

These are some ways to reverse a string on Linux and Windows. There are other ways to achieve this, using different utilities or programming languages.

Via shell script on Linux

sh-3.2# vi reverse.sh
#### Start Script #####
#!/bin/bash
input_string=”$1″
reverse_string=””

input_string_length=${#input_string}
for (( i=$input_string_length-1; i>=0; i– ))
do
reverse_string=”$reverse_string${input_string:$i:1}”
done

echo “$reverse_string”
##### End Script #####

Let’s run it:

sh-3.2# chmod 775 reverse.sh
sh-3.2# ./reverse.sh Etienne
enneitE

Via powershell script on Windows

#Let’s use the script reverse.ps1 below.
######
$string=”Etienne”
$string_array=$string -split “”
[array]::Reverse($string_array)
$string_array -join ”

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#####Output#####
PS C:\Users\etienne_noumen\Documents\Etienne\Scripting> .\reverse.ps1

E t i e n n e

"Become a Canada Expert: Ace the Citizenship Test and Impress Everyone with Your Knowledge of Canadian History, Geography, Government, Culture, People, Languages, Travel, Wildlife, Hockey, Tourism, Sceneries, Arts, and Data Visualization. Get the Top 1000 Canada Quiz Now!"

enneitE

Via powershell script on Windows in one line

([regex]::Matches($String,’.’,’RightToLeft’) | ForEach {$_.value}) -join ”

Via batch script on Windows

::Note: ReverseStr also calls StrLen
::and string length is not greater than 80 chars
:: but can be changed.

@echo off
SetLocal EnableDelayedExpansion
cls
set Str=Etienne
call :StrLen %Str%
echo Length=%Len%
call :ReverseStr %Str%
echo String=%Str%
echo Reverse Str=%Reverse%
exit /b

::—————-
:: Calc Var Length
::—————-
:: %*=Str to Check
:: Returns %Len%
:: —————
:StrLen %*
set Data=%*
for /L %%a in (0,1,80) do (
set Char=!Data:~%%a,1!
if not “!Char!”==”” (
set /a Len=%%a+1
) else (exit /b)
)
exit /b

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::—————
:: Reverse String
::—————
:: %* Str to Reverse
:: Returns %Reverse%
::——————
:ReverseStr %*
set Data=%*
call :StrLen %Data%
for /L %%a in (!Len!,-1,0) do (
set Char=!Data:~%%a,1!
set Reverse=!Reverse!!Char!
)
exit /b

Via perl script on Windows or Linux

Via python script on Windows or Linux

def reverse_string(a_string)
return a_string[::-1]
reverse_string(“etienne”) returns “enneite”
Source:

http://www.computing.net/answers/programming/reverse-a-string-in-dos/26004.html

August 18, 2015January 3, 2023

Linux Boot process

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Let’s describe Linux Boot Process:

The Linux boot process involves several stages, in which the operating system performs various tasks to prepare the system for use.

When the system is powered on, the BIOS (Basic Input/Output System) or the UEFI (Unified Extensible Firmware Interface) performs a power-on self-test (POST) to check the hardware components and to load the bootloader.
The bootloader, such as GRUB (GRand Unified Bootloader), is responsible for loading the operating system kernel and transferring control to it.
The operating system kernel, which is the core of the operating system, initializes the system and starts the system services.
The system services, such as the device drivers, are loaded and initialized.
The operating system loads the user profile and starts the user interface, such as the desktop or the login screen.
The user can log in and start using the system.

This is a general overview of the Linux boot process. The exact sequence of events may vary depending on the specific distribution of Linux and the hardware configuration of the system.

BIOS	Basic INPUT/OUTPUT System. Executes MBR
MBR	Master Boot Record Executes GRUB
GRUB	Grand Unified Bootloader Executes kernel
KERNEL	Kernel Executes /sbin/init
INIT	Init Executes Run level programs
Run Level	Run Level Programs are executed from /etc/rc.d/rc*.d/

As power comes up the BIOS is given control
BIOS runs self tests, usually including cursory memory tests.
The BIOS then loads the first sector of the disk to be used for booting and transfers control to it.
The MBR code varies. One version will chain to the code in the first sector of the boot partition (Windows), another will load a bootloader. Windows boot proceeds from code and information in the boot partition.
The bootloader chooses kernel location and version
The bootloader prepares kernel and initrd image in memory, transfers control to kernel
Loading kernel modules
Discovering hardware and load additional kernel modules to support it
Looking for disks
R/O mount of / partition so that it can potentially be checked and repaired
init process spawn
/etc/inittab read and executing
Mounting all FSes from /etc/fstab
runlevels running (based on default runlevel in /etc/inittab) or another init method such as systemd or upstart
rc.local
login prompt

Source:

1. http://unix.stackexchange.com/questions/27034/discribe-in-details-tha-boot-process-of-any-linux-system

1. http://www.thegeekstuff.com/2011/02/linux-boot-process/

Watch video here
http://www.slideshare.net/dominiquec/understanding-the-boot-process

August 13, 2015January 3, 2023

Monitor Macbook

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How to Monitor Macbook with one single command?

$sudo sysdiagnose -f ~/Desktop/

The result is a compressed file named sysdiagnose_YYYY.MM.DD_HH-MM-SS-TTTT.tar.gz and it contains the following:
Accessibility
BluetoothTraceFile.pklg
DiagnosticMessages
Etienne’s SystemConfiguration
airport_info.txt
apsd-status.txt
bc_stats.txt
bootstamps.txt
brctl.tar.gz
breadcrumbs.txt
crashes_and_spins
darwinup.txt
dig-results.txt
disks.txt
diskutil.txt
error_log.txt
filecoordination_dump.txt
footprint-all.txt
fs_usage.txt
fsck_hfs_user.log
fsck_hfs_var.log
gpt.txt
ifconfig.txt
ioreg
ipconfig.txt
kextstat.txt
launchctl-list.txt
locale.txt
logs
lsappinfo.txt
lsmp.txt
lsof.txt
lsregister.txt
microstackshots
microstackshots_lastday.txt
microstackshots_lasthour.txt
microstackshots_lastminute.txt
mount.txt
netstat
nfsstat.txt
odutil.txt
pluginkit.txt
pmset_everything.txt
powermetrics.txt
ps.txt
ps_thread.txt
reachability-info.txt
resolv.conf
scutil.txt
smcDiagnose.txt
spindump.txt
stackshot-last-sym.log
sysctl.txt
sysdiagnose.log
system_profiler.spx
talagent.txt
taskinfo.txt
thermal.txt
top.txt
var_run_resolv.conf
vm_stat.txt
zprint.txt

You can use the top command to monitor the resources of your Macbook in real-time. The top command is a built-in utility that shows the processes that are currently running on the system, along with information about their CPU and memory usage.

To use the top command, open a terminal window and type top. The output will show the list of processes, sorted by their CPU usage, with the most CPU-intensive processes at the top. You can use the q key to exit the top command.

Here are some of the key options you can use with the top command:

-o: sort the processes by a particular resource, such as CPU usage or memory usage. For example, top -o cpu will sort the processes by CPU usage.
-s: specify the delay between updates. For example, top -s 2 will update the display every 2 seconds.
-u: show the process for a particular user. For example, top -u username will show the processes for the user with the specified username.

You can use these options in combination to customize the output of the top command. For example, to monitor the CPU usage of the processes owned by a particular user, you can use the following command:

top -o cpu -s 2 -u username

August 13, 2015April 19, 2016

List only regular file names in a directory

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How to List only regular file names in a directory on Linux and Windows

Listing regular files in a directory without including . and .. files.

On Linux
Solution 1:$ ls -p | grep -v /
Solution 2: $ ls -F | grep -v ‘[/@=|]’
Solution 3: $for list in `ls` ; do ls -ld $list | grep -v ^d > /dev/null && echo $list ; done ;
Solution4:$ for list in `ls` ; do ls -ld $list | grep ^d > /dev/null || echo $list ; done ;
Solution5 (exclude sym links):$ for list in `ls` ; do ls -ld $list | grep -v ^l > /dev/null && echo $list ; done ;
On Windows
Solution 1: dir /a-d /b >..\File_List.txt

July 28, 2015April 19, 2016

Set Date and time via command line

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Let’s find out how to set Date and time via command line on linux and windows:

On Linux via terminal
System time (Must have sudo privilege)
date -s ‘2015-07-28 15:27:30’
Hardware time
Let’s set the hardware clock to the current system time:
hwclock –systohc

On Windows via command prompt terminal
System time (Must have Administrator privilege)
date
The current date is: 07/28/2015
Enter the new date: (mm-dd-yy)_
time
The current time is: 15:34:03.44
Enter the new time: _

Posted on July 28, 2015July 19, 2016

prompt and read input variables from keyboard

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Let’s find how to prompt and read input variables from keyboard while executing a script using shell, perl, python, batch and powershell (windows and Linux)

On Linux via shell
read -p “Enter your name: ” name
echo “Hi, $name. Let’s be friend!”

On Windows via powershell
$name=read-host “Enter your name:”
write-host “Hi $name, Let’s be friend!”
On Windows via batch
Set /p Name=”Enter your name:”
echo “Hi %name%, Let’s be friend!”
On Windows or Linux via perl
print “Enter your name “;
my $name = ;
chomp $name; # Get rid of newline character at the end
print “Hello $name, let’s be friend”;
On Windows or Linux via python
name=input(“Enter your name: “)
print (“Hello ” + name + ” let’s be friend”)

Posted on March 29, 2015April 19, 2016

List all processes holding a specific port

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How to list all processes holding a specific port on Linux and windows via command line

Let’s find all processes pid using port 80 on linux and windows:

On Linux
lsof -i:80

On Windows
netstat -aon | findstr :80

Name _____	Value _______
Alberta	Calgary
British Columbia	Vancouver
Ontario	Toronto
Quebec	Montreal

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Let’s find how to prompt and read input variables from keyboard while executing a script using shell, perl, python, batch and powershell (windows and Linux)

On Linux via shell

On Windows via powershell

On Windows via batch

On Windows or Linux via perl

On Windows or Linux via python

How to list all processes holding a specific port on Linux and windows via command line

On Linux

On Windows