bash script search file

skarychinezeguie · 12-19-2010, 07:59 PM

total newb here. call me a script kiddie if you want but here is what i need to do and what i have.

need to:
search a hidden log file for a specific string, find what comes after that part, and then output the result to a variable or something that can be used by an application or other script to carry out further actions.

example:

self.selectedAuxStateStr = Available

self.selectedAuxStateStr = 2 Training

i need to find "self.selectedAuxStateStr = " and then determine what state it is currently in. also, since the log is in chronological order i will need to start at the bottom and find the LAST instance of this string.

here is what i have so far

Code:

( date; uname -a ) >>logfile
# Time and machine name
echo ---------------------------------------------------------- >>logfile
tail -n $LINES /var/log/system.log | tr -d "\"'" | xargs | fmt -s >>logfile
echo >>logfile
echo >>logfile
echo "self.selectedAuxStateStr = " | tr '' ' '
echo "success"
exit 0

mike11 · 12-19-2010, 08:08 PM

grep can output line before and after the match. check the man page.
my guess is that you'll need something like

Code:

var=$(grep -B 1 -A 1 <string> <file>)

replace <string> and <file> with the string ur searching for and the file you work on.
The above example will output lines containing the string plus one line before and after and var will hold the output.

catkin · 12-19-2010, 08:50 PM

Code:

var=$( grep self.selectedAuxStateStr /var/log/system.log | tac | head -1 | sed 's/^.*= //' )

grail · 12-19-2010, 09:01 PM

Code:

var=$(awk -F" *= *" '/self\.selectedAuxStateStr/{x=$2}END{print $2}' /var/log/system.log)