Finding text in a file

Question

This is what i am trying to achieve, seems it has some errors. Escape sequences in the strings yet to be added

search_string="LoadModule rewrite_module "${ORACLE_HOME}/ohs/modules/mod_rewrite.so"
insert_string1="LoadModule reqtimeout_module "${ORACLE_HOME}/modules/mod_reqtimeout.so"
insert_string2="<IfModule reqtimeout_module>RequestReadTimeout header=20-40,MinRate=500 body=20,MinRate=500 </IfModule>"
grep "$insert_string1" httpds.conf;
if [ $? -ne 0 ]; then
    sed -r -e ":a;/${search_string}/ {n;s/$/${insert_string1}/};ta" httpds.conf
    sed -r -e ":a;/${insert_string1}/ {n;s/$/${insert_string2}/};ta" httpds.conf
    echo "Configuration inserted successfully"
fi

#################### Output File should look as follows

LoadModule unique_id_module "${ORACLE_HOME}/ohs/modules/mod_unique_id.so"
LoadModule setenvif_module "${ORACLE_HOME}/ohs/modules/mod_setenvif.so"
LoadModule context_module "${ORACLE_HOME}/ohs/modules/mod_context.so"
LoadModule rewrite_module "${ORACLE_HOME}/ohs/modules/mod_rewrite.so"
LoadModule reqtimeout_module "${ORACLE_HOME}/modules/mod_reqtimeout.so"
<IfModule reqtimeout_module>
   RequestReadTimeout header=20-40,MinRate=500 body=20,MinRate=500 
</IfModule>"

LoadModule dumpio_module "${ORACLE_HOME}/ohs/modules/mod_dumpio.so"

Answer 1

You can check this one with sed:

sed -i '/string/a SampleInsert/' configfile.txt

if -i is not supported, then simply you can redirect the output to a new file:

sed '/string/a SampleInsert/' configfile.txt > output_file.txt

Answer 2

By append do you mean add to the end of the line following the line with the match? If so, the trick is to get sed to rescan for the pattern else it will miss the line after the one where SampleInsert is added. You need to use the label and go to label commands:

$ cat configfile.txt
1 gary     tty7
2 mysearchstringgary     tty7
3 testingmysearchstring gary     tty7
4 gary     tty7mysearchstring
5
6 gary     tty7mysearchstring
7 gary     tty7
8 gary     tty7
$
$
$ sed -r -e ':a;/mysearchstring/ {n;s/$/SampleInsert/};ta' configfile.txt
1 gary     tty7
2 mysearchstringgary     tty7
3 testingmysearchstring gary     tty7SampleInsert
4 gary     tty7mysearchstringSampleInsert
5 SampleInsert
6 gary     tty7mysearchstring
7 gary     tty7SampleInsert
8 gary     tty7
$ 

Since you didn't supply test data I just made some up with the search text in various places. Don't forget a blank line for testing.

The sed command uses -r -e args for extended, regular expressions. Inside of the single quotes are multiple commands, separated by semi-colons. First set a label named a, then look for lines matching "mysearchstring". If found, run the commands surrounded by the curly braces and separated by semi-colons. n means read the next line into the pattern buffer since that's the line you want to append the text to. Search for the end of the line and append "SampleInsert". Now, THAT line may have the search text so it needs to be searched as well. That's why the next command is ta, which means go to label a. Label a is just before the search for the search string so that causes the current line to be rescanned for the search pattern.

EDIT: If used inside of a bash script where the search and insert values are variables defined in the script:

#!/bin/bash

readonly searchstr='mysearchstring'
readonly insertstr='SampleInsert'

sed -r -e ":a;/${searchstr}/ {n;s/$/${insertstr}/};ta" configfile.txt

Or passed in a arguments to the script (should have some error handing but this is just to illustrate):

$ fixfile.sh mysearchstr SampleInput

#!/bin/bash

readonly searchstr=$1
readonly insertstr=$2

sed -r -e ":a;/${searchstr}/ {n;s/$/${insertstr}/};ta" configfile.txt

Answer 3

Using awk:

#!/bin/bash

FIND=".el"; # assign whatever variable you want
APPEND="Hi";
awk -v find="$FIND" -v append="$APPEND" '{print $0 (index($0, find) != 0 ? "\n"append : "")}' configfile.txt