Replace selection with output of external command

Question

Assuming I have a line in a file with XXXX being a placeholder I have selected via v as follows:

XXXX Some other text

How can I change only the XXXX with the output of an external command, such as date +%Y%m%d?

I got as far as

:'<,'>!date +\%Y\%m\%d 

but that replaced the whole line.

Answer 1

You could delete the text and insert the output of a command using CtrlR-=:

CTRL-R {0-9a-z"%#*+:.-=}                                        i_CTRL-R
                Insert the contents of a register.  Between typing CTRL-R and
                the second character, '"' will be displayed to indicate that
                you are expected to enter the name of a register.
 …
                                                        i_CTRL-R_=
                        '='     the expression register: you are prompted to
                                enter an expression (see expression)

For the expression, you can use the system() function to run external commands.

After selecting the text, press c, then <c-r>= and use system('date +%Y%m%d') as the expression.

Answer 2

If you put the cursor on such a line you can:

• 0 to put the cursor in the first column.
• f Space to put the cursor in the first blank.
• i Enter Esc to split the line.
• l to move the cursor one line up.
• :.!date +\%Y\%m\%d to execute the command.
• J to join the lines again.

From :h :visual_example:

Currently the ":" command works on whole lines only. When you select part of a line, doing something like ":!date" will replace the whole line. If you want only part of the line to be replaced you will have to make a mapping for it. In a future release ":" may work on partial lines.

See also :h visual-operators for details.

From this comment: You can also try the vis or NrrwRgn plugin. Both should handle it just fine. (Thanks @christian-brabandt for the tip).

Answer 3

Create a temporary mapping for such replacements. For example:

:vnoremap qq c<C-R>=system('wc -c | perl -pe chomp', @")<CR><ESC>

Then in visual mode you can select text, type qq and it'll be replaced by the command output. In this example wc -c will process your selection, which is the @" parameter. perl -pe chomp is needed to remove a trailing newline from the output.

Answer 4

Try this:

:let @a = system('date +\%Y\%m\%d')[:-2]
:'<,'>g/XXXX/s/XXXX/\=@a/g

• The first line saves the output of date command into register a, with the ending newline removed.
• The second line globally inspect your selection and mark the lines containing XXXX (g/XXXX/), and
• replace all the instances of the XXXX with the content of register a (s/XXXX/\=@a/g)

See :h let-@ and :h :global as well as the "Sublist" section in :h list-index

Answer 5

Plugin: Visual Block Commands (vis) by DrChip

Installation of vis.vba.gz and dependency cecutil.vba.gz into vim8 packpath

# shell brace expansion (bash >=3.0, zsh>=2.6)
$ mkdir -p ~/.vim/pack/manual/start/{vis,cecutil}
$ vim http://www.drchip.org/astronaut/vim/vbafiles/vis.vba.gz
:UseVimball ~/.vim/pack/manual/start/vis
:e http://www.drchip.org/astronaut/vim/vbafiles/cecutil.vba.gz
:UseVimball ~/.vim/pack/manual/start/cecutil

OP example becomes

:'<,'>B !date +\%Y\%m\%d