A Bash script is a plain text file which contains a series of commands. It allows you to perform a series of actions. Bash scripting is an essential skill for any developer and system administrator to perform tasks efficiently and automate repetitive tasks. Like any other programming languages, you will be creating variables &
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This extends Bash script interview Q&As – variables & arrays Q01 How will you concatenate strings in Bash? A01 In Bash, when variables or strings are written one after another, they automatically concatenate.
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#!/bin/bash #global variable offline="&offline=true" #global variable with concatenation reqParams="oauth_nonce=$(uuidgen | sed 's/-//g')" # generate uuid & replace - with nothing reqParams="${reqParams}&oauth_signature_method=HMAC-SHA256" reqParams="${reqParams}&oauth_version=1.0" reqParams="${reqParams}${offline}" echo $reqParams |
Outputs:
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oauth_nonce=E95431982C784E82B0FCAD0B8B2780B8&oauth_signature_method=HMAC-SHA256&oauth_version=1.0&offline=true |
Shell varaiable expansion modifiers Q02 What are Shell or Bash parameter or variable expansion...
Q01 What is a conditional expression in bash? A01 A conditional in Bash scripting is made up of two things: a conditional statement and one or more conditional operators. if statement examples with arithmetic comparisons like -eq, -lt, … Read more ›...
Q01 Can you explain the below code? temp.sh:
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#!/bin/bash function func { if command -v python3 &> /dev/null then echo "$(command -v python3)" return 0 fi if command -v python2 &> /dev/null then echo "$(command -v python2)" return 0 fi return 2 } export -f func ./temp2.sh |
temp2.sh:
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#!/bin/bash pythonPath=$(func) exitCode=$? echo "The python path is" $pythonPath echo "The function func exit code is" $exitCode |
Run temp.sh:
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$ ./temp.sh |
A01 The above code is used to find out if python is installed and if installed find the location of the executable. … Read more ›...
Q01 What is an IFS in Bash? A01 IFS is a special variable in Bash which is used to control the field separator for line parsing. By default, IFS is set to a space, a tab, and a newline character, which means that fields in a string are separated by...
Q01 How will you run a Bash script? A01 Bash scripts, like scripts written in other programming languages, can be run in a wide variety of ways. Permission to run Firstly, the script needs to have the right permission to execute the script. … Read more ›...
Q1. Can the following code be further improved?
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class CashBalance { def balance = 0.0; def initBalance(def initBalance) {this.balance = initBalance } def addCredits(def credits) {this.balance = balance + credits } def subtractDebits(def credits) {this.balance = balance - credits } } def cashBal = new CashBalance(); cashBal.initBalance(50000.00); cashBal.addCredits(10000.00); cashBal.subtractDebits(20000.00); println "Current balance = ${cashBal.balance}" //40000.00 is the ouput |
A1. Yes, it can be made a bit more elegant with the builder design pattern. For example, we can return the “CashBalance” object from each mathod by adding the keyword “this” … Read more ›...
Common Table Expressions or CTE’s for short are used in SQL to simplify complex joins and subqueries, and to provide a means to query hierarchical data such as an organisational chart. This was also introduced in MySQL 8 – Using https://www.db-fiddle.com/. … Read more ›...
Uses DB-FIDDLE for the code example with PostgreSQL v17.
Q01 How will you go about defining tables with primary key, foreign keys and unique constraints?
A01 The main purpose of a primary key in a table is to uniquely identify each record.
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The following is a very popular SQL job interview question. Q. What is the difference between “Truncate” and “Delete” commands? A. TRUNCATE TABLE_NAME always locks the table and page but not each row, … Read more ›...
Firstly, decide on the specification version. If you are using FIX spec 4.4 then go to https://fixspec.com/FIX44. The tutorials with QuickFIX/J used NewSingleOrder as the request. The message has the fields like Tag number. … Read more ›...
Let’s look at some of the key commands developers & data engineers will be using with git. Clone Firstly, you need to clone a project from a remote repository to your local repository. You can get the ssh or https URL from your remote repository like GitHib, BitBucket, … Read...
Let’s look at how we can undo changes in Git. Often we need to rollback or stash our changes. Q01. When is git restore used? A01. The “restore” command is used to 1) Undo the effects of git add, … Read more ›...
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