- 01Setting up (what you'll need)
- 02Your first shell script (echo)
- 03Using variables
- 04Command-line arguments ($1, $2 ...)
- 05Branching (the if statement)
- 06Repeating (the for loop)
- 07Repeating (the while loop)
- 08Writing your own function
- 09Working with arrays
- 10Command substitution ($())
- 11Working with strings (parameter expansion)
- 12Reading from standard input (read)
- 13Exit status and && / ||
- 14Pipes and redirection
- 15The case statement
- 16Arithmetic ($(( )))
- 17The basics of grep, sed and awk
- 18Argument checks and error handling
- 19Function return values and exit codes
- 20[Project] Build a small log-tallying script
Repeating (the for loop)
This lesson covers looping in a shell script with a for statement.
Writing for variable in list; do ... done repeats the block for each value in the list. You can also build a numeric range by combining it with a command such as seq 1 5.
The sample code writes for i in 1 2 3 4 5; do echo $i; done to print the numbers 1 through 5 in order.
A common early stumble is forgetting do and done. They are the start and end markers — the equivalent of {} in other languages — and always come as a pair.
In professional work, for loops are used constantly to apply the same operation to a list of files or servers.
๐งช This site can't compile or run Shell Script directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser โ nothing is sent anywhere).