Let's consider that I have the following bash script called time.bash:

date -d @$1 

This script converts the epoch timestamp to its corresponding date as the following:

$ ./time.bash 1267619929
qua mar  3 09:38:49 -03 2010

Now let's suppose I'm editing the following file using Vim:

1267619929 word word 
1267619935 word word 
1267619931 word word 
1267619946 word word

Considering that I'm working just on a single line, I'd like to save the timestamp 1267619929 on the register a with "aye, execute the script time.bash with the register a content as input, and save its output on another register (let's say register b). Is it possible to do this kind of stuff on Vim?

1 Answer 1


You could do this:

let @b=system("time.bash " . @a)

The @a is register a and @b is register b. The system(...) runs a command and returns the output. The result is a line, so when you paste it, you get a new line.

See :help system().

Another way is:

call setreg("b", system("time.bash " . @a), "v")

Here you can set the mode for the register. The lower case v sets it to characterwise. With it you can paste the result within a line.

See :help setreg()

You could also do it without first copying the value to register a. Put the cursor on the numeric value and execute:

call setreg("b", system("time.bash " . expand("<cword>")), "v")

The expand("<cword>") is expanded to the word under the cursor.

See :help <cword> and :help expand().

  • Thanks!! That was exactly what I needed... Now that I've played a little with these commands I've realized that without the . on let @b=system("time.bash " . @a) the command doesn't work. Just as a curiosity, what is the . purpose inside the system function? Jun 21, 2019 at 6:11
  • 2
    @RafaelMuynarsk The dot is the operator for string concatenation.
    – Ralf
    Jun 21, 2019 at 6:47
  • Or (untested) :s/<cword>/\=system("time.bash" . submatch(0)/
    – D. Ben Knoble
    Jun 21, 2019 at 12:30

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