wiki.bash-hackers.org/syntax/ccmd/while_loop.md

====== The while-loop ======

===== Synopsis ===== <code> while <LIST1> ; do <LIST2> done </code>

===== Description ===== The while-loop is relatively simple in what it does: it executes the command list ''<LIST1>'' and if the exit code of it was 0 (TRUE) it executes ''<LIST2>''. This happens again and again until ''<LIST1>'' returns FALSE.

This is exactly the opposite of the until loop.

:!: Like all loops (both ''for''-loops, ''while'' and ''until''), this loop can be

• terminated (broken) by the ''break'' command, optionally as ''break N'' to break ''N'' levels of nested loops
• forced to immediately do the next iteration using the ''continue'' command, optionally as ''continue N'' analog to ''break N''

==== Return status ====

The return status is the one of the last command executed in ''<LIST2>'', or ''0'' (''TRUE'') if none was executed.

===== Examples =====

===== Portability considerations =====

===== See also =====

• Internal: The until loop
• Internal: code examples of the read builtin command to see how you can loop over lines