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Question: Can you give some examples of few common Signals in Linux?
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Answer: Please find below few common signals:
• SIGINT: This is the signal generated when a user presses Control-C to terminate the program from terminal.
• SIGALRM: This one is generated when a timer set by an alarm function goes off.
• SIGSTOP: This signal tells LINUX to pause a process to be resumed later.
• SIGCONT: This signal asks LINUX to resume the processed paused earlier.
• SIGABRT: This is generated when a process executes the abort function.
• SIGKILL: This one is sent to a process to cause it to terminate at once.
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Question: Is it possible to use regular expressions in Bash scripts?
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Answer: Regular expressions (regex) are implemented using the =~ operator, below please find some sample code:
if [[ $inputvalue =~ [0-9]+ ]]
then
echo "Input contains numbers"
fi
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Question: Can you use Arrays in Bash scripts?
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Answer: Within Bash script one can create and use arrays in following way, point to remember that the array index is zero-based:
names=(“John” “Scott″) # Declare
names[2]=“Michael” # Add
unset ‘names[1]’ # Remove
echo "Hello ${names[0]}, how can I help you?" # Access a particular record
echo "Array length: ${#names[@]}" # Get length
for i in “${names[@]}”; do echo $i; # Print all records in an array
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Question: How can you define STEP value in a FOR Loop within Bash script?
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Answer: Bash (version 4.0+) provides inbuilt support for setting up a step value using {START..END..INCREMENT} syntax:
#!/bin/bash
for i in {0..10..2}
do
echo "Welcome $i times"
done
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