The problem is that more than 1 line could have been added while your script slept
The best is to perform (Pseudo-code) :
line count (wc -l), calc the difference with previous count, tail the difference from your file, set your previous-count-variable to the new count, sleep, loop.
Code:
OLD=0
while true
do
COUNT=$(wc -l < $FILE)
DIFF=$((COUNT-OLD))
if [ $DIFF -gt 0 ]
then
tail -n $DIFF $FILE
OLD=$COUNT
elif [ $DIFF -lt 0 ] # Can happen (logrotate...)
OLD=0
continue
fi
sleep 1
done
Hello,
I have a script that monitors files uploaded via ftp. After a successful upload, the file name is written to the pipe.
There is another program that reads this pipe and allows automatically run any program or script ( say test.sh ) to process the newly uploaded file.
cat test.sh... (2 Replies)
Hello,
I am intending to perform a check based on number of "@" , present in a line in a log file . The idea is basically to perform a check on cc or bcc sender, based on an email log, which shows all the for email address. Say if the number of @ is more than 30, I will consider it as a mass... (12 Replies)
I have 2 files. I basically want to search both of them to see if the 1st column ($1) matches and if it matches then check to see if the 2nd column ($2) matches, then execute some code showing the results of the matches.
File 1:
AAA 123
misc blah
BBB 456
CCC 789
File 2:
... (2 Replies)
Hi,
I have one dir which has N subdirs.For ex:
/home/user/Project_Src
/home/user/Project_Src/Dir_A
/home/user/Project_Src/Dir_A/subdir/sub_dir2
/home/user/Project_Src/Dir_A/subdir/sub_dir3
/home/user/Project_Src/Dir_B
/home/user/Project_Src/Dir_B/Build
i want to create a folder with... (2 Replies)
hi,
i have a service on unix platform, it will generate traces in a particular folder
i want to check using shell script if traces exist, then perform some action else continue to be in loop.
filename is service.tra
can you please help?
thanks (4 Replies)
Hi,
I want to access files from different directories (for example: /home/dir1/file1 , /home/dir2/file2 ...) Like this i have to access these files(file1, file2...). (3 Replies)
Hi All,
I need to create a script to monitor a dir for new files with ext .err and also it should b a non empty files. and perform a action or command .
We have a new ETL application that runs on a linux server, every times a etl fails it creates a .err file or updates the existing .err... (4 Replies)
Hello,
I'm attempting to write a tool that checks an IP address for existing PTR records then if there are no PTR records does a ping to see if it response.
Then if there is no response, it should print a message saying
This is what I have so far.
#!/usr/bin/perl
$nxdomain =... (4 Replies)
Hi,
I am new to awk/unix and am trying to put together an awk script to perform an action similar to vlookup between the two csv files.
Here are the contents of the two files:
File 1:
Date,ParentID,Number,Area,Volume,Dimensions
2014-01-01,ABC,247,83430.33,857.84,8110.76... (9 Replies)
Discussion started by: Prit Siv
9 Replies
LEARN ABOUT V7
diff
DIFF(1) General Commands Manual DIFF(1)NAME
diff - differential file comparator
SYNOPSIS
diff [ -efbh ] file1 file2
DESCRIPTION
Diff tells what lines must be changed in two files to bring them into agreement. If file1 (file2) is `-', the standard input is used. If
file1 (file2) is a directory, then a file in that directory whose file-name is the same as the file-name of file2 (file1) is used. The
normal output contains lines of these forms:
n1 a n3,n4
n1,n2 d n3
n1,n2 c n3,n4
These lines resemble ed commands to convert file1 into file2. The numbers after the letters pertain to file2. In fact, by exchanging `a'
for `d' and reading backward one may ascertain equally how to convert file2 into file1. As in ed, identical pairs where n1 = n2 or n3 = n4
are abbreviated as a single number.
Following each of these lines come all the lines that are affected in the first file flagged by `<', then all the lines that are affected
in the second file flagged by `>'.
The -b option causes trailing blanks (spaces and tabs) to be ignored and other strings of blanks to compare equal.
The -e option produces a script of a, c and d commands for the editor ed, which will recreate file2 from file1. The -f option produces a
similar script, not useful with ed, in the opposite order. In connection with -e, the following shell program may help maintain multiple
versions of a file. Only an ancestral file ($1) and a chain of version-to-version ed scripts ($2,$3,...) made by diff need be on hand. A
`latest version' appears on the standard output.
(shift; cat $*; echo '1,$p') | ed - $1
Except in rare circumstances, diff finds a smallest sufficient set of file differences.
Option -h does a fast, half-hearted job. It works only when changed stretches are short and well separated, but does work on files of
unlimited length. Options -e and -f are unavailable with -h.
FILES
/tmp/d?????
/usr/lib/diffh for -h
SEE ALSO cmp(1), comm(1), ed(1)DIAGNOSTICS
Exit status is 0 for no differences, 1 for some, 2 for trouble.
BUGS
Editing scripts produced under the -e or -f option are naive about creating lines consisting of a single `.'.
DIFF(1)
02-22-2010
