The given command uses the `sed` (Stream Editor) command-line utility....

The given command uses the sed (Stream Editor) command-line utility. Here's a breakdown of what it does:

Code:

sed -i "s% $%%g" $file

Breakdown:

• sed: A stream editor that performs basic text transformations on input files or streams.
• -i: The -i option stands for "in-place editing." This means that the edits are directly applied to the file specified by $file rather than printing the output to the terminal or standard output.
• "s% $%%g":
  • The s at the beginning stands for "substitute."
  • % is being used as the delimiter (instead of the usual /). This is allowed in sed and can be helpful if the delimiter / is already present in the search/replacement patterns.
  • $: A pattern that matches a space character ( ) at the end of a line. The $ signifies the end of a line in regular expressions.
  • %: The delimiter between the search pattern and the substitution (here, there is no substitution value).
  • Empty substitution pattern: This means the matching text (space at the end of a line) will be replaced with nothing (effectively deleting it).
  • g: The global flag tells sed to apply this substitution to all occurrences in the line, but in this case, it is redundant because there can be at most one match of $ per line (since it specifically targets the end of the line).

$file:

• $file is a shell variable that contains the path to the file that sed will operate on.

What the Code Does:

The command removes trailing spaces (spaces at the end of lines) from the file specified by the $file variable, modifying the file directly in place.