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Top Forums Shell Programming and Scripting blank line deletion in a file using perl Post 302294326 by vguleria on Thursday 5th of March 2009 03:42:04 AM
Old 03-05-2009
Hi Rikxik,

thanks for the reply.

But it's not working for me. let me elaborate:

my script has to get the last line in a file to a perl variable as a string. Now, the file has last line as empty one. Hence i can't directly put it to my string variable as i have to get the last non empty line into the variable.

e.g.,

cat input.txt
Hi there
<blank line>

my variable has to get the last line as:

$myvar=`tail -1 input.txt`;

The problem is that last line is empty and my requirement is the string which is last line in a file and is non empty.



Regards,
Vinod.

Quote:
Originally Posted by rikxik
Code:
$ cat input
A|3k|sdgs|211

C|dd|
D||gfgsfg|ff

22|fdfdfsdfsdf
$ perl -ne 'print unless(/^\s*$/);' input
A|3k|sdgs|211
C|dd|
D||gfgsfg|ff
22|fdfdfsdfsdf

 

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gets(n) 						       Tcl Built-In Commands							   gets(n)

__________________________________________________________________________________________________________________________________________________

NAME
gets - Read a line from a channel SYNOPSIS
gets channelId ?varName? _________________________________________________________________ DESCRIPTION
This command reads the next line from channelId, returns everything in the line up to (but not including) the end-of-line character(s), and discards the end-of-line character(s). ChannelId must be an identifier for an open channel such as the Tcl standard input channel (stdin), the return value from an invocation of open or socket, or the result of a channel creation command provided by a Tcl extension. The channel must have been opened for input. If varName is omitted the line is returned as the result of the command. If varName is specified then the line is placed in the variable by that name and the return value is a count of the number of characters returned. If end of file occurs while scanning for an end of line, the command returns whatever input is available up to the end of file. If chan- nelId is in nonblocking mode and there is not a full line of input available, the command returns an empty string and does not consume any input. If varName is specified and an empty string is returned in varName because of end-of-file or because of insufficient data in non- blocking mode, then the return count is -1. Note that if varName is not specified then the end-of-file and no-full-line-available cases can produce the same results as if there were an input line consisting only of the end-of-line character(s). The eof and fblocked commands can be used to distinguish these three cases. EXAMPLE
This example reads a file one line at a time and prints it out with the current line number attached to the start of each line. set chan [open "some.file.txt"] set lineNumber 0 while {[gets $chan line] >= 0} { puts "[incr lineNumber]: $line" } close $chan SEE ALSO
file(n), eof(n), fblocked(n), Tcl_StandardChannels(3) KEYWORDS
blocking, channel, end of file, end of line, line, nonblocking, read Tcl 7.5 gets(n)
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