18.26 Replace Regexp in a File
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We can replace strings within a line that match a regular expression using perl. For example, to replace strings that are at the beginning of a line that contain two asterisks, then an 8 digit date, then two more asterisks and a space, with an inline call to an R function in a bookdown document:
$ perl -pi.bak -e 's|^\*\*(\d{8})\*\* |`r#cite_date($1)` |' chapt1.Rmd
$ meld chapt1.Rmd.bak chap1.RmdIn this example -i is used to do the replacement in place and .bak
is added so that the original file kept as a backup in case anything
should go wrong. We can use meld to compare the files to
confirm all works as expected.
Once we are comfortable and have tested the process, we can repeat this for all Rmd files int eh current directory:
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