done

View documentation for the for keyword

$ tldr for

$ tldr while

$ tldr select

$ tldr until

do
  [commands]
done

The done reserved word in POSIX shells (Bash, Dash, Zsh, Ksh) terminates the body of a loop started by do. It is essential for constructs like for, while, and until, marking the end of repeated commands.

Without done, the shell parser encounters syntax errors as it cannot delineate loop bodies. It has no arguments or options; its presence alone signals loop termination.

Example usage:
for file in *.txt; do
  echo "Processing $file";
done

This iterates over .txt files, echoing each. Nesting is supported, with each do requiring a matching done. Mismatched pairs cause syntax error: unexpected end of file or similar.

done processes sequentially; loops run in current shell context, inheriting variables and traps. Redirects apply to entire bodies if placed before do. It's a core scripting element for automation, file processing, and control flow.

Requires matching do; nesting must balance precisely. No standalone use; syntax error otherwise. Ignores trailing arguments silently in Bash.

while read line; do
  echo "$line" | tr 'a-z' 'A-Z';
done < input.txt

Converts file to uppercase line-by-line.

for dir in /tmp/*; do
  for file in "$dir"/*; do
    ls -l "$file";
  done;
done

Originated in Bourne shell (1977, Version 7 Unix). Standardized in POSIX.1-1988; evolved minimally across shells for compatibility.

bash(1), dash(1), zsh(1), ksh(1)