tail and grep log and mail (linux)
You want to send an email when emailing errors occur? That might fail ;)
You can however try something like this:
tail -f $log |grep --line-buffered error |while read linedo echo "$line" | mail -s subject "$email"doneWhich for every line in the grep output sends an email.
Run above shell script with
nohup ./monitor.sh &so it will keep running in the background.
I'll have a go at this. Perhaps I'll learn something if my icky bash code gets scrutinised. There is a chance there are already a gazillion solutions to do this, but I am not going to find out, as I am sure you have trawled the depths and widths of the cyberocean. It sounds like what you want can be separated into two bits: 1) at regular intervals obtain the 'latest tail' of the file, 2) if the latest tail actually exists, send it by e-mail. For the regular intervals in 1), use cron. For obtaining the latest tail in 2), you'll have to keep track of the file size. The bash script below does that - it's a solution to 2) that can be invoked by cron. It uses the cached file size to compute the chunk of the file it needs to mail. Note that for a file myfile another file .offset.myfile is created. Also, the script does not allow path components in the file name. Rewrite, or fix it in the invocation [e.g. (cd /foo/bar && segtail.sh zut), assuming it is called segtail.sh ].
#!/usr/local/bin/bashfile=$1size=0offset=0if [[ $file =~ / ]]; then echo "$0 does not accept path components in the file name" 2>&1 exit 1fiif [[ -e .offset.$file ]]; then offset=$(<".offset.$file") fiif [[ -e $file ]]; then size=$(stat -c "%s" "$file") # this assumes GNU stat, possibly present as gstat. CHECK! # (gstat can also be Ganglias Status tool - careful).fiif (( $size < $offset )); then # file might have been reduced in size echo "reset offset to zero" 2>&1 offset=0fiecho $size > ".offset.$file"if [[ -e $file && $size -gt $offset ]]; then tail -c +$(($offset+1)) "$file" | head -c $(($size - $offset)) | mail -s "tail $file" foo@barfi