Shell Script to fill the target defined in XML file - shell

Question

Suppose there is one file.txt in which text is written as mentioned below:-
ABC
EFG
XYZ
In another xml, there is one empty body target named(compile) defined.
<project>
<compile>
.
.
.
start //from here till EOF
shell
script
xyz
</compile>
</project>
I need a shell script which fill the content in between the target defined . After executing the script it should look as mentioned below in output tag.It will be done for the entire content written in file.txt file.
Output:-
<!-- ...preceding portions of input document... -->
<project>
<compile>
componentName="ABC"
componentName="EFG"
componentName="XYZ"
start
shell
script
xyz
</compile>
</project>
<!-- ...remaining portions of input document... -->

Answer 1

Use a proper XML parser. XMLStarlet is one tool fit for the job:
#!/bin/bash
# ^^^^- important, not /bin/sh
# read input file into an array
IFS=$'\n' read -r -d '' -a pieces <file.txt
# assemble target text based on expanding that array
printf -v text 'componentName=%s\n' "${pieces[#]}"
# Read input, changing all elements named "compile" in the default namespace
# ...to contain our target text.
xmlstarlet ed -u '//compile' -v "$text" <in.xml >out.xml

Answer 2

You can do what you are attempting (to some degree) with sed and a while read -r loop. For example, you can fill a temporary file with the contents of your xml file from line 1 to the <targettag> with
sed -n "1, /^${ttag}$/p" "$xfn" > "$ofn" ## fill output to ttag
(where xfn is your xml file name and ofn is your output file name)
You can then read all values from your text file and prepend componentName=" and append " with:
while read -r line; do ## read each line in ifn and concatenate
printf "%s%s\"\n" "$cmptag" "$line" >> "$ofn"
done <"$ifn"
(where ifn is your input file name)
And finally, you can write the closing tag to end of your xml file to your output file with:
sed -n "/^${ttag/</<[\/]}$/, \${p}" "$xfn" >> "$ofn"
(using parameter expansion with substring replacement to add the closing '/' to the beginning of <targettag>.
Putting it altogether, you could do something like:
#!/bin/bash
ifn="f1"
xfn="f2.xml"
ofn="f3.xml"
ttag="${1:-<targettag>}" ## set target tag
cmptag="componentName=\"" ## set string to prepend
sed -n "1, /^${ttag}$/p" "$xfn" > "$ofn" ## fill output to ttag
while read -r line; do ## read each line in ifn and concatenate
printf "%s%s\"\n" "$cmptag" "$line" >> "$ofn"
done <"$ifn"
## fill output from closing tag to end
sed -n "/^${ttag/</<[\/]}$/, \${p}" "$xfn" >> "$ofn"
Input Files
$ cat f1
ABC
EFG
XYZ
$ cat f2.xml
<someschema>
<targettag>
</targettag>
</someschema>
Example Use/Output
$ fillxml.sh
$ cat f3.xml
<someschema>
<targettag>
componentName="ABC"
componentName="EFG"
componentName="XYZ"
</targettag>
</someschema>
(you can adjust the indentation to fit your needs)
Addition After Changes to Question
The changes needed to handle writing from start to end after adding the componentName="..." tags are simple. However, the commonality of the word start exemplifies why the answer by Charles encourages you to use an XML tool rather than a simple script. Why? If the word 'start' occurs anywhere else in your .xml file before your intended start, the script will fail by writing for the first occurrence of start to the end.
That said, if this is a simple on-off conversion and start doesn't occur otherwise, then the changes to the script to accomplish your desired output are easy:
#!/bin/bash
ifn="f1"
xfn="another.xml"
ofn="f3.xml"
ttag="${1:-<compile>}" ## set target tag
cmptag="componentName=\"" ## set string to prepend
sed -n "1, /^${ttag}$/p" "$xfn" > "$ofn" ## fill output to ttag
## read each line in ifn and concatenate
while read -r line || [ -n "$line" ]; do
printf "%s%s\"\n" "$cmptag" "$line" >> "$ofn"
done <"$ifn"
## fill output from 'start' to end
sed -n "/^start/, \${p}" "$xfn" >> "$ofn"
Input Files
$ cat f1
ABC
EFG
XYZ
$ cat another.xml
<project>
<compile>
start
shell
script
xyz
</compile>
</project>
Example Use/Output
$ cat f3.xml
<project>
<compile>
componentName="ABC"
componentName="EFG"
componentName="XYZ"
start
shell
script
xyz
</compile>
</project>
Look it over and let me know if you have questions.