sed variable replacement

Question

I have tried this countless ways, time to throw in the towel and ask the master...

#!/bin/bash

# Read in the VERSION.header file, this is a plain text file
# with returns, which in some of my tests, I am loosing the returns and getting
# one string wrapped only by the shell width
VERSION_HEADER=`cat VERSION.header`

sed 's/_VERSION_HEADER_/"$VERSION_HEADER"/g' DOCUMENTATION

The string '_VERSION_HEADER_' exists currently as line 1 in the file DOCUMENTATION. The file 'VERSION.header' has about 18 lines in it.

I am not attached to using sed. All I am looking to do is read in a file which acts as a template, store that files data as a variable, read in a second file, store it as a variable. Look in the second file for a marker, replace the marker with the data from the first file.

Example:

$cat VERSION.header

hi, this is my header file, how are you today
good, that is nice, great
have a nice day, k, thx, bye.

$cat DOCUMENTATION

_VERSION_HEADER_

# This is a documentation file, please read it
# If you do not read it, you will get stuck to the toilet.

And the result should be:

hi, this is my header file, how are you today
good, that is nice, great
have a nice day, k, thx, bye.

# This is a documentation file, please read it
# If you do not read it, you will get stuck to the toilet.

Answer 1

sed -i "s/_VERSION_HEADER_/$VERSION_HEADER/g" DOCUMENTATION

EDIT

Sorry, finally got your problem. You have a multi-line pattern. This may help. Also consider using Python instead:

#!/usr/bin/env python

f = open('doc.txt', 'r')
doc = f.read()
f.close()

f = open('VERSION.header', 'r')
versionHeader = f.read()
f.close()

doc = doc.replace('_VERSION_HEADER_', versionHeader)
print doc

This may be less efficient, though.

Answer 2

How about something like this:

#!/bin/bash

while read oneline; do
    VERSION_HEADER=${VERSION_HEADER}'\n'${oneline};
done < VERSION.header

sed 's/_VERSION_HEADER_/'"${VERSION_HEADER}"'/g' DOCUMENTATION

Answer 3

Give this a try:

sed -e '/_VERSION_HEADER_/{r VERSION.header' -e ';d}' DOCUMENTATION

That reads in the file when it finds the template string, then deletes the template string.

Answer 4

awk

awk 'FNR==NR{s=s" "$0"\n";next}/_VERSION_HEADER_/{$0=s}1' version.header documentation

Answer 5

Maybe take a look at man 1 ed as well:

# http://wiki.bash-hackers.org/doku.php?id=howto:edit-ed
[[ $(grep -c _VERSION_HEADER_ DOCUMENTATION) -eq 1 ]] && \
cat <<-'EOF' | sed -e 's/^ *//' -e 's/ *$//' | ed -s DOCUMENTATION
   H
   /_VERSION_HEADER_/i
   .
   .c
   .
   .r VERSION.header
   wq
EOF

Answer 6

Using (FreeBSD) sed do something like:

VERSION_HEADER="$(sed -E -e 's/\\/\\\\/g' -e 's/&/\\\&/g' -e 's|/|\\/|g' -e 's/$/\\/g' VERSION.header)"

# note the space after ${VERSION_HEADER}
sed -E -i "" "/_VERSION_HEADER_/s/_VERSION_HEADER_/${VERSION_HEADER} /" DOCUMENTATION