Shifting arguments (shift) in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the shift command do in a bash script?

The shift command moves all the positional parameters to the left by one. This means $2 becomes $1, $3 becomes $2, and so on. It helps process arguments one by one.

intermediate

How do you shift by more than one argument at a time?

You can pass a number to shift, like shift 2, to move the positional parameters left by that many places at once.

intermediate

What happens if you shift more times than the number of arguments?

If you shift more than the number of arguments, the positional parameters become empty. Trying to access them will give empty values.

beginner

Why is shift useful in scripts that process command-line arguments?

It lets you handle each argument one at a time in a loop. After processing $1, you use shift to move to the next argument easily.

beginner

Example: What will be the output of this script?<br>

#!/bin/bash
while [ "$#" -gt 0 ]; do
  echo "Argument: $1"
  shift
 done

The script prints each argument on its own line, one by one, until no arguments remain. For example, if run as ./script.sh apple banana cherry, it outputs:<br>Argument: apple Argument: banana Argument: cherry

What does shift do in a bash script?

A Prints all arguments

B Deletes all arguments

C Moves positional parameters left by one

D Reverses the order of arguments

shift moves all positional parameters left by one, so $2 becomes $1, etc.

How do you shift by two arguments at once?

A shift 2

B shift -2

C shift twice

D shift --two

You pass the number to shift, like shift 2, to move two arguments at once.

What happens if you shift more times than the number of arguments?

A Script crashes

B Positional parameters become empty

C Arguments repeat

D Nothing changes

Shifting beyond the number of arguments empties the positional parameters.

Why use shift in a loop processing arguments?

A To count arguments

B To skip arguments

C To print arguments backwards

D To process arguments one by one

shift helps move through arguments one at a time in a loop.

If a script starts with $1 = apple and runs shift, what is $1 now?

A The original $2

B apple

C empty

D The original $3

After shift, $1 becomes what was originally $2.

Explain how the shift command helps in processing command-line arguments in bash scripts.

Think about how you can handle each argument step-by-step.

Describe what happens when you use shift 3 in a script with five arguments.

Consider how the numbering of arguments changes after shifting.