I am writing a small shell script to receive an input and match against a text file.
However, the input would be a bigger string than the string in the file, against which I want a match.
User input:
abc-de-ef-gh1
Text in file:
This is test,-de-ef-gh,This is test
I want a positive result if I grep user-input with existing file.
How can I achieve this? I couldn't do it with grep.
You have a file with patterns. grep can read the patterns with its -f option. If you want to check whether a string, $input, matches a pattern in patterns.txt, you may do
printf '%s\n' "$input" |
if grep -q -f patterns.txt; then
echo 'matches'
else
echo 'does not match'
fi
This would run grep over the contents of the string with the patterns in patterns.txt. In bash you could instead use a here-string:
if grep -q -f patterns.txt <<<"$input"; then
echo 'matches'
else
echo 'does not match'
fi
The -q stops grep from producing output (we're only interested in the exit status).
If the patterns are fixed strings (not regular expressions), use -F with grep in addition to the other flags (grep -qF -f ...).
Using bash, cut and grep:
read -p "Hey user, input something: " $n
printf "Match "
grep -m 1 -q -f <(cut -d, -f2 file) <<< "$n" || printf "not "
printf "found.\n"
Notes:
cut is used to extract the middle field from filegrep searches for that middle field in the user input string.printf provides some feedback.
abc-d-ef-gh1? How aboutf-gh? How about-gh1? How aboutghor1? Describe the processes by which you would answer those questions; i.e., describe the rules that determine whether a string should match a line. Please do not respond in comments; edit your question to make it clearer and more complete.