Replace certain token with the content of a file (using a bash-script) - bash

Question

I have a file containing some text and the words INSERT_HERE1 and INSERT_HERE2. I'd like to replace these words with the content of file1.txt and file2.txt respectively.
I suspect sed or awk could pull it off but I've basically never used them.

Answer 1

Sed does have a built-in read file command. The commands you want would look something like this:
$ sed -e '/INSERT_HERE1/ {
r FILE1
d }' -e '/INSERT_HERE2/ {
r FILE2
d }' < file
This would output
foo
this is file1
bar
this is file2
baz
The r command reads the file, and the d command deletes the line with the INSERT_HERE tags. You need to use the curly braces since sed commands and multi-line input since sed commands have to start on their own line, and depending on your shell, you may need \ at the end of the lines to avoid premature execution. If this is something you would use a lot, you can just put the command in a file and use sed -f to run it.

Answer 2

If you are okay with Perl you can do:
$ cat FILE1
this is file1
$ cat FILE2
this is file2
$ cat file
foo
INSERT_HERE1
bar
INSERT_HERE2
baz
$ perl -ne 's/^INSERT_HERE(\d+)\s+$/`cat FILE$1`/e;print' file
foo
this is file1
bar
this is file2
baz
$

Answer 3

This is not tested, but would be pretty close to what you need:
sed -e "s/INSERT_HERE1/`cat file1.txt`/" -e "s/INSERT_HERE2/`cat file2.txt`/" <file >file.out
It will not properly handle a file with slashes in it, though, so you may need to tweak it a bit.
I'd recommend Perl instead, though. Something like this:
#!/usr/bin/perl -w
my $f1 = `cat file1.txt`;
my $f2 = `cat file2.txt`;
while (<>) {
chomp;
s/INSERT_HERE1/$f1/;
s/INSERT_HERE2/$f2/;
print "$_\n";
}
This assumes that INSERT_HERE1 and INSERT_HERE2 may only appear once per line, and that the file1.txt does not include the text INSERT_HERE2 (wouldn't be difficult to fix, though). Use like this:
./script <file >file.out

Answer 4

This is suitable for small substitution files that may be substituted many times:
awk 'BEGIN {
while ((getline line < ARGV[1]) > 0) {file1 = file1 nl line; nl = "\n"};
close (ARGV[1]); nl = "";
while ((getline line < ARGV[2]) > 0) {file2 = file2 nl line; nl = "\n"};
close (ARGV[2]);
ARGV[1] = ""; ARGV[2] = "" }
{ gsub("token1", file1);
gsub("token2", file2);
print }' file1.txt file2.txt mainfile.txt
You may want to add some extra newlines here and there, depending on how you want your output to look.

Answer 5

Easily done with Bash. If you need it to be POSIX shell let me know:
#!/bin/bash
IFS= # Needed to prevent the shell from interpreting the newlines
f1=$(< /path/to/file1.txt)
f2=$(< /path/to/file2.txt)
while read line; do
if [[ "$line" == "INSERT_HERE1" ]]; then
echo "$f1"
elif [[ "$line" == "INSERT_HERE2" ]]; then
echo "$f2"
else
echo "$line"
fi
done < /path/to/input/file

Answer 6

This snippet replaces any section that is specified in the upper array. For e.g. here
<!--insert.txt-->
with the contents of "insert.txt"
#!/bin/bash
replace[1]=\<!--insert.txt--\> ; file[1]=insert.txt
replace[2]=\<!--insert2.txt--\> ; file[2]=insert2.txt
replacelength=${#replace[#]}
cat blank.txt > tmp.txt
for i in $(seq 1 ${replacelength})
do
echo Replacing ${file[i]} ...
sed -e "/${replace[i]}/r ${file[i]}" -e "/${replace[i]}/d" tmp.txt > tmp_2.txt
mv tmp_2.txt tmp.txt
done
mv tmp.txt file.txt
If you're not afraid of .zip files you can try this example as long as it is online: http://ablage.stabentheiner.de/2013-04-16_contentreplace.zip

Answer 7

I would use perl's in place replacement with -i.ext option
perl -pi.bak -e 's|INSERT_HERE1|`cat FILE1`|ge;
s|INSERT_HERE2|`cat FILE2`|ge;' myfile
Then, use diff myfile.bak myfile to verify: