IT – Engineering – Cloud – Finance
IT, Engineering, Entrepreneurship, Sports, Finances, Life, Success, Failure
You can translate the content of this page by selecting a language in the select box.
import subprocess
subprocess.call(['sh shell_script.sh arguments'])
or
import sys, os
os.system("sh shell_script.sh arguments")
Output Example
You can translate the content of this page by selecting a language in the select box.
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.
I- Networking:
II- Operating System
1&1 Web Hosting
| 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.) |
III- File System
IV- Databases
V- Scripting
Learn more at http://career.guru99.com/top-50-linux-interview-questions/
Real Time Linux Jobs
You can translate the content of this page by selecting a language in the select box.
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
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 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
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
You can translate the content of this page by selecting a language in the select box.
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
#Let’s use the script reverse.ps1 below.
######
$string=”Etienne”
$string_array=$string -split “”
[array]::Reverse($string_array)
$string_array -join ”
#####Output#####
PS C:\Users\etienne_noumen\Documents\Etienne\Scripting> .\reverse.ps1
E t i e n n e
enneitE
([regex]::Matches($String,’.’,’RightToLeft’) | ForEach {$_.value}) -join ”
::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
::—————
:: 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
def reverse_string(a_string)
return a_string[::-1]
reverse_string(“etienne”) returns “enneite”
Source:
You can translate the content of this page by selecting a language in the select box.
| 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/ |
Source:
You can translate the content of this page by selecting a language in the select box.
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 translate the content of this page by selecting a language in the select box.
Listing regular files in a directory without including . and .. files.
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 ;
Solution 1: dir /a-d /b >..\File_List.txt
You can translate the content of this page by selecting a language in the select box.
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
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: _
You can translate the content of this page by selecting a language in the select box.
read -p “Enter your name: ” name
echo “Hi, $name. Let’s be friend!”
$name=read-host “Enter your name:”
write-host “Hi $name, Let’s be friend!”
Set /p Name=”Enter your name:”
echo “Hi %name%, Let’s be friend!”
print “Enter your name “;
my $name =
chomp $name; # Get rid of newline character at the end
print “Hello $name, let’s be friend”;
name=input(“Enter your name: “)
print (“Hello ” + name + ” let’s be friend”)
You can translate the content of this page by selecting a language in the select box.
Let’s find all processes pid using port 80 on linux and windows:
lsof -i:80
netstat -aon | findstr :80
