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Full Discussion: bash: read file line by line (lines have '\0') - not full line has read???
Top Forums Shell Programming and Scripting bash: read file line by line (lines have '\0') - not full line has read??? Post 302398043 by alex_5161 on Tuesday 23rd of February 2010 05:47:08 PM
Old 02-23-2010
Quote:
Originally Posted by radoulov
I'm not sure if bash can handle null bytes (usually they don't belong to text files).
As a quick fix I would use another tool for parsing files containing null bytes.

By the way, some shells (I tried with zsh and pdksh using read -r) seem to handle it.
I have checked it here (Solaris) and -r does not make a trick.

Quote:
Originally Posted by joeyg
Can you use the tr command to trim out those characters?
Yes, I can, but it is as 'hands up' on problem Smilie
By now I do it in perl, and that is pretty useful way, but I'd like to now how to be in such situation.
What I do not like in the 'tr' - need to create another file. Also, the removing (-d) is not useful as I need to read positioned fields, but replacing with spaces works.
Code:
 > cat grb|tr '\0',' '| while IFS= read ln; do echo $ln; done;
hello word done
this next line
last ln
 >

I am not sure: that way with the 'cat ..', it is, again, done on whole file, isn't it?
(And, it seems to me, there is some glitch in bash-2.05 in processing pipe by while (something about that I've experiensed about half year ago.) Seems something with asigning variables...
So, another point why I do not like that solution by 'tr..'
 

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LEARN ABOUT DEBIAN

flow-cat

flow-cat(1)						      General Commands Manual						       flow-cat(1)

NAME

       flow-cat -- Concatenate flow files

SYNOPSIS

       flow-cat  [-aghmp]   [-b  big|little]   [-C  comment]   [-d  debug_level]   [-o	filename]   [-t start_time]  [-T start_time]  [-z z_level]
       [file|directory ...]

DESCRIPTION

       The flow-cat utility processes files and/or directories of files in the flow-tools format.  The resulting concatenated data set is  written
       to the standard output or file specified by -o.	If file is a single dash (`-') or absent, flow-cat will read from the standard input.

OPTIONS

       -a	 Do not ignore filenames that begin with tmp.

       -b big|little
		 Byte order of output.

       -C Comment
		 Add a comment.

       -d debug_level
		 Enable debugging.

       -g	 Sort file list by capture start time before processing.

       -h	 Display help.

       -m	 Disable the use of mmap().

       -p	 Preload headers.  Use to preserve meta information such as lost flows.

       -o file	 Write to file instead of the standard out.

       -t start_time
		 Select flow files up to start_time.  If used with -T select files between start_time and end_time.

       -T end_time
		 Select flow files after end_time.  If used with -t select files between start_time and end_time.

       -z z_level
		 Configure compression level to  z_level.  0 is disabled (no compression), 9 is highest compression.

       file|directory...
		 Process the files and/or directory.

TIME
/DATE parsing
       start_time  and	end_time  parsing  is  implemented with getdate.y, a commonly used function to process free-form time date specifications.
       Example usage borrowed from cvs:
	   1 month ago
	   2 hours ago
	   400000 seconds ago
	   last year
	   last Monday
	   yesterday
	   a fortnight ago
	   3/31/92 10:00:07 PST
	   January 23, 1987 10:05pm
	   22:00 GMT

EXAMPLES

       Concatenate all flow files begining with ft-v05.2001-05.01, use flow-print to display the results.

	   flow-cat ft-v05.2001-05-01.* | flow-print

       Concatenate flow files in /flows/krc4, store store the output in compressed.flows at compression level 9 (best).  The headers are preloaded
       so  various  metadata  such  as	the flow count is correct in the result.  Filenames begining with tmp which are typically in-progress flow
       files from flow-capture are not processed.

	   flow-cat -p -z9 /flows/krc4 > compressed.flows

BUGS

       None known.

AUTHOR

       Mark Fullmer maf@splintered.net

SEE ALSO

       flow-tools(1)

																       flow-cat(1)
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