Bash

Loops Commands

Iterate in Bash scripts. Learn for loops, while loops, and loop control for repetitive tasks.

11 commands

Pro Tips

Use 'for file in *.txt; do ...; done' for iterating over file patterns.

Use 'while read -r line; do ...; done < file' to process files line by line.

Common Mistakes

Avoid 'for f in $(cat file)' - it breaks on spaces. Use 'while read' instead.

Commands

Range loop

$ for i in {1..10}; do echo $i; done

Loop through number range.

C-style for loop

$ for ((i=0; i<10; i++)); do echo $i; done

Loop with counter variable.

File loop

$ for f in *.txt; do echo "$f"; done

Loop through files.

Read file lines

$ while IFS= read -r line; do echo "$line"; done < file

Loop through file lines safely.

Infinite loop

$ while true; do sleep 1; done

Run infinite loop.

Until loop

$ until [ -f file.txt ]; do sleep 1; done

Loop until condition is true.

Loop with index

$ for i in "${!arr[@]}"; do echo "$i: ${arr[$i]}"; done

Loop with array indices.

Break loop

$ for i in {1..10}; do [ $i -eq 5 ] && break; echo $i; done

Exit loop early with break.

Continue loop

$ for i in {1..5}; do [ $i -eq 3 ] && continue; echo $i; done

Skip iteration with continue.

Process substitution

$ while read -r line; do echo "$line"; done < <(command)

Read from command output.

Loop with step

$ for i in {0..20..5}; do echo $i; done

Loop with custom step value.