Bash command to insert contents of one file into a specific part of another file

veryangryman

cat file_to_insert
1
2
cat original_file
a
b
c

I want to put the contents of file_to_insert on the original file between b and c

So it would look like

a
b
1
2
c

Skrynesaver

$ split -l 2 original_file original_part_ && cat original_part_aa file_to_insert original_part_ab
a
b
1
2
c

28064212

sed "/^b$/r file_to_insert" original_file

This will insert the contents of file_to_insert after every line that exactly matches 'b'.

srsly78

Use head/tail and grep to do this. Grep to find the line before/after the special section.

https://linux.die.net/man/1/grep - look at the -A and -B options.

veryangryman

Cheers y'all. Settled on the sed command

veryangryman

One more query on this

sed "/^${last_string}$/r ${tmp_symlinks_file_part_2}" /var/tmp/sym_links.ini.$$

Is there a way to do the replacement at X lines after the instance of the last string.

In my case, i want to do it 6 lines down

srsly78

Yes, with the grep -A or -B options.

Use grep to extract the section you want to change, then pipe this to sed.

veryangryman

srsly78 wrote: »

Yes, with the grep -A or -B options.

Sorry to sound silly but how to shoehorn that into the current command?

veryangryman

Answering my own q

last_details=$(grep -A8 ${last_string} /var/tmp/sym_links.ini.$$)
        sed "/^${last_details}$/r ${tmp_symlinks_file_part_2}" /var/tmp/sym_links.ini.$$ > /var/tmp/sym_links.ini.$$.tmp2

veryangryman

Seems to have trouble doing a multi line sed (as the grep gives us a multiline variable)


sed: -e expression #1, char 24: unterminated address regex

last_details=$(grep -A7 ${last_string} /var/tmp/sym_links.ini.$$)
sed "/^${last_details}$/r ${tmp_symlinks_file_part_2}" /var/tmp/sym_links.ini.$$ > /var/tmp/sym_links.ini.$$.tmp2

srsly78

Pipe grep -A to head -n 1 to get one line.

veryangryman

Similar ish query

sed "/^\[DWH_DBSPACES_LOCATION\]$/r ${sysmain_content}" /var/tmp/sym_links.ini.$$ > /var/tmp/sym_links.ini.$$.tmp1

How to alter this so that [DWH_DBSPACES_LOCATION] appears at the end rathjer than the start of the replaced string