Shell script to extract 2 values from all files? - linux

Question

I have a directory full of files like this:
[Location]
state=California
city=Palo Alto
[Outlet]
id=23
manager=John Doe
I want to write a small script, that outputs one line for each file like this:
John Doe,Palo Alto
How do I do that? I suspect some grep and looping. So far I have:
#!/bin/bash
echo Manager,City > result.txt
for f in *.config
do
cat "$f" | grep manager= >> result.txt
cat "$f" | grep city= >> result.txt
done
but that's of course incomplete since grep returns the whole line on its own line and I only want the part after the first = sign.

Answer 1

echo Manager,City > result.txt
for f in *.config; do
manager=$(awk -F= '$1=="manager" {print $2}' "$f")
city=$( awk -F= '$1=="city" {print $2}' "$f")
echo "$manager,$city"
done >> result.txt
awk -F= uses an equal sign as the field separator, and then checks for the desired variables ($1) and prints their values ($2). $(cmd) captures the output of a command and yields strings that can be assigned to the two variables $manager and $city.

Answer 2

Similar to John Kugelman's answer but using grep.
echo Manager,City > result.txt
for file in *.config; do
name=$(grep -oP '(?<=manager\=).*' "$file")
location=$(grep -oP '(?<=city\=).*' "$file")
echo "$name,$location"
done >> result.txt

Answer 3

You can do this with a single awk command, as per the following transcript:
pax> cat 1.config
[Location]
state=California
city=Palo Alto
[Outlet]
id=23
manager=John Doe
pax> cat 2.config
[Location]
state=Western Australia
city=Perth
[Outlet]
id=24
manager=Pax Diablo
pax> awk '
/^city=/ {gsub (/^city=/, "", $0); city=$0}
/^manager=/{gsub(/^manager=/, "", $0); print $0 "," city}
' *.config
John Doe,Palo Alto
Pax Diablo,Perth
Note that this assumes the city comes before the manager, and that all files have both city and manager. If those assumptions are incorrect, the awk script becomes a little more complex but it's still doable.
In that case, it becomes something like:
awk '
FNR==1 {city = ""; mgr = ""}
/^city=/ {gsub (/^city=/, "", $0); city = $0}
/^manager=/ {gsub (/^manager=/, "", $0); mgr = $0}
{if (city!="" && mgr!=""){
print mgr "," city; city = ""; mgr = "";
}}
' *.config
What this does is to make the order irrelevant. It resets the city and manager variables to empty string at the start of each file and just stores them in the cases where it finds the relevant lines. After every line, if both are set, it prints and clears them.