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Top Forums Shell Programming and Scripting Wait/if Generated kind of operation Post 302915475 by linuxUser_ on Wednesday 3rd of September 2014 09:35:22 AM
Old 09-03-2014
Quote:
Originally Posted by RavinderSingh13
Dear linuxuser_

Could you please be more clear on your requirement, as I understood you are requesting for checking a file's existance. Let me give you an example for same.

Code:
if [[ -f "file2" ]] 
then 
echo 
"file2 is present."
else 
echo "file2 is NOT present." 
fi

In my case file is present so it will give following output. Also please refer man test for more information. Hope this helps.

Code:
file2 is present.

Thanks,
R. Singh
file will exist all the time and it will get update with data(like log file).
like push_back in cpp, data will be pushed into the file after every iteration.
I want to read Time value.
But trick is I want to read last two time occurrences and compare file existence.
If you see in my previous reply, last two time values are 2 and 3.
I want to check whether data files(these files are different) for
these time are present or not.

In the same case, since simulation is still going there will be no data files for time 3. After finished with 2nd simulation data some data will be written. but in log file I can see Time =3 as well which is not done yet.

Let me know if you still didn't understand.

Thanks for help.

---------- Post updated at 07:05 PM ---------- Previous update was at 06:56 PM ----------

Making my explanation even more simple:
How can I read last two occurrences of time value?
 

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comm(1) 							   User Commands							   comm(1)

NAME
comm - select or reject lines common to two files SYNOPSIS
comm [-123] file1 file2 DESCRIPTION
The comm utility reads file1 and file2, which must be ordered in the current collating sequence, and produces three text columns as output: lines only in file1; lines only in file2; and lines in both files. If the input files were ordered according to the collating sequence of the current locale, the lines written will be in the collating sequence of the original lines. If not, the results are unspecified. OPTIONS
The following options are supported: -1 Suppresses the output column of lines unique to file1. -2 Suppresses the output column of lines unique to file2. -3 Suppresses the output column of lines duplicated in file1 and file2. OPERANDS
The following operands are supported: file1 A path name of the first file to be compared. If file1 is -, the standard input is used. file2 A path name of the second file to be compared. If file2 is -, the standard input is used. USAGE
See largefile(5) for the description of the behavior of comm when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes). EXAMPLES
Example 1 Printing a list of utilities specified by files If file1, file2, and file3 each contain a sorted list of utilities, the command example% comm -23 file1 file2 | comm -23 - file3 prints a list of utilities in file1 not specified by either of the other files. The entry: example% comm -12 file1 file2 | comm -12 - file3 prints a list of utilities specified by all three files. And the entry: example% comm -12 file2 file3 | comm -23 -file1 prints a list of utilities specified by both file2 and file3, but not specified in file1. ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of comm: LANG, LC_ALL, LC_COLLATE, LC_CTYPE, LC_MESSAGES, and NLSPATH. EXIT STATUS
The following exit values are returned: 0 All input files were successfully output as specified. >0 An error occurred. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWesu | +-----------------------------+-----------------------------+ |CSI |enabled | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
cmp(1), diff(1), sort(1), uniq(1), attributes(5), environ(5), largefile(5), standards(5) SunOS 5.11 3 Mar 2004 comm(1)
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