Group commands instead of repeating redirects

Problem

Each `>> file` redirection opens the file, writes, and closes it. In a long script that appends frequently, the syscall overhead and the risk of interleaved writes from other processes both grow. Grouping the writes batches them into a single open.

Bad

echo "header" >> report.txt
date >> report.txt
uptime >> report.txt

Good

{
  echo "header"
  date
  uptime
} >> report.txt

Explanation

This is also clearer to read — anyone scanning the script sees one redirection target instead of three identical paths.

When It Matters

Repeating >> file on ten consecutive lines opens, seeks, and closes the file ten times. On a local disk that is merely wasteful; on a network filesystem, or when another process is tailing the file, it also opens ten windows in which interleaved writes can appear between your lines. Grouping the commands makes the append atomic from the script’s point of view and turns a block of near-identical lines into one readable unit — which is the real win when the block later grows a conditional or a loop.

Second Example

Exceptions

Two or three appends scattered through unrelated logic are clearer left alone — grouping is worth it when the appends are consecutive and belong together. If the lines are separated by other work that must happen between writes, keep them separate and ignore the warning.

Faq