r -- edit and re-execute previous command

r edit and re-execute previous command	KornShell Built-in

The r command (a built-in KornShell alias) re-executes a command you ran previously, possibly editing it first. Commands are obtained from your command history file; see fc and sh for more details.

The specifier tells which command you want to re-execute. It can have any of the following forms:

An unsigned number (n): r run the command with that number.
A negative number (-n): r runs the command that came n commands before the current one.
A character string (x): r runs the most recent command beginning with x.

If no specifier is given, r runs the most recent command.

The old=new feature lets you edit a command before running it. old and new must be character strings. r replaces the first occurrence of old in the command arguments with new and then re-executes the command.

EXAMPLES

r cp

runs the most recently executed command beginning with the characters cp. The cp could be the whole command name or it could be part of a longer command name (for example, cpio).

cp file1 /dir
r 1=2
r 2=3

This is equivalent to

cp file1 /dir
cp file2 /dir
cp file3 /dir

Compare this with

cp file1 /dir/file1
r 1=2

which is equivalent to

cp file1 /dir/file1
cp file2 /dir/file1

Since r only replaces the first occurrence of the old string 1, the second 1 does not change. This shows that you have to be careful when you use the substitution feature.

r is a built-in MKS KornShell alias, defined with