Sponsored Content
Full Discussion: Confusing sed error message
Top Forums Shell Programming and Scripting Confusing sed error message Post 303027482 by Scrutinizer on Sunday 16th of December 2018 04:26:14 PM
Old 12-16-2018
Quote:
Originally Posted by Ralph
[..]
--- Post updated at 03:15 PM ---

Actually, what I'm trying to do is remove duplicate pairs from a file like this:
Code:
==: dir1/dir2/file1 dir3/dir4/file2
==: dir5/dir6/file3 dir1/file4
==: dir3/file5 dir3/file6
==: dir1/file4 dir5/dir6/file3
==: dir3/dir4/file2 dir1/dir2/file1
==: dir3/file6 dir3/file5

I find out it doesn't really work if I redirect the file into a while-loop that uses read to read a line, like this:
Code:
while read $LINE ; do
   swap column 2 with column 3
   remove swapped line from file (using sed)
done < file

I got the idea because while read works line by line from the beginning of the file the swapped line is always located behind the other one so if I remove it read will never see it. But apparently the entire original file is still available to read no matter what I remove.

Is there is a better approach?
Assuming the fields in your input file are whitespace separated, you could try this approach:
Code:
awk '!A[$2,$3]++ && !A[$3,$2]++' file

These 2 Users Gave Thanks to Scrutinizer For This Post:
 

9 More Discussions You Might Find Interesting

1. Solaris

(Need Help) confusing format on solaris 10

Hi All, Very need help about format syntax on solaris 10. I have done install Solaris 10 OS on sun fire v245 but currently i have a problem to use "format" command to display partition info for my hard drive. i cannot enter the format menu, below is captured display : # format Searching... (7 Replies)
Discussion started by: bucci
7 Replies

2. Shell Programming and Scripting

Confusing Error

Hi all, Just subscribed to this forum. Not a regular user of Unix.:) I did the following: We have a directory structure /a/b/c5/ Where c5 is the only directory inside b. export ANOOP=/a/b/c*/ echo $ANOOP=/a/b/c5/ I have to create a symbolic link to anoop.txt in the directory... (2 Replies)
Discussion started by: Pankajakshan
2 Replies

3. Shell Programming and Scripting

Confusing me......!!!!!!

Hiii... There... I am making a Script in which I am taking the value of a variable "var" through key board. But I want, if no values are supplied for "var" for more than 5 seconds then script shuld automatically exit.Script is as follow : #cat abc #!/bin/bash echo "Enter Your Choice : "... (4 Replies)
Discussion started by: prashantshukla
4 Replies

4. UNIX and Linux Applications

pikdev requirements confusing

I am looking at installing PiKdev which needs libqt3-mt and kdelibs4-dev. The installed package is qt-r1008952-i486-1 which claims to be a gui toolkit. find / -name "*libqt*" yields nothing with mt just a lot of support, compatible, and access widgets. Normally I would consider this a no go but... (0 Replies)
Discussion started by: slak0
0 Replies

5. Shell Programming and Scripting

Confusing find command option

Hi, I am a little bit confusing of using find command. Actually, I am planning to delete the files whatever the files are existing in the day before yesterday. So, I am writing the command like this. find . -name "*.txt" -ctime -2 { here I am confusing, if I will use +2 or +1 also I am... (5 Replies)
Discussion started by: nagraju.allam
5 Replies

6. Shell Programming and Scripting

sed garbled error message in bash shell

Sed garbled error. Cannot determine why the sed command to insert a line at the beginning of a file will not work on declared variables. outfile='DAR.V2.2012115.1.CSV' testfile='totality_request.sql' header_prefix='DATA FILE' no_ext_file=`echo $outfile |sed 's/\(.*\)..../\1/'` ... (6 Replies)
Discussion started by: smenago
6 Replies

7. Shell Programming and Scripting

sed to extract a multiline subject from a mail message

I'm trying to extract a subject from a mail message but my subject example has 2 lines. How can I manage to extract it and write a string at the end of it? Consider this example: From: test@domain.com Subject: Re: U =?ISO-8859-1?Q?qu=EA=3F!=3F!=3F!!_wtff_=E7=E3o_=ED=F3?= ... (6 Replies)
Discussion started by: twisterbr
6 Replies

8. Shell Programming and Scripting

Ps command output confusing

Hi, I ran a script named cat item when I searched for this script using command PS I get two process . I don't understand this. Also this script has run for 15 minutes but the time is showing as 0:00:confused::confused: ps -ef | grep cat_item catmgr 4508 4486 0 05:10:29 ? 0:00... (5 Replies)
Discussion started by: TomG
5 Replies

9. Shell Programming and Scripting

Confusing of some basic awk

1. increase file space first, double space a file: awk '1;{print ""}' I probably can understand it:print a blank line every time.But when I read triple space a file I am confused: awk '1;{print "\n"}' doesn't it meaning print a blank line every time too? 2. number each line of file, but... (6 Replies)
Discussion started by: hhdzhu
6 Replies
SHAR(1net)							  Wang Institute							SHAR(1net)

NAME
shar - create file storage archive for extraction by /bin/sh SYNOPSIS
shar [-abcmsuv] [-p prefix] [-d delim] files > archive DESCRIPTION
shar prints its input files with special command lines around them to be used by the shell, /bin/sh , to extract the files later. The out- put can be filtered through the shell to recreate copies of the original files. shar allows directories to be named, and shar prints the necessary commands (mkdir & cd) to create new directories and fill them. shar will not allow existing files to be over-written; such files must be removed by the user extracting the files. OPTIONS
-a All the options. The options: -v -c -b -p <tab>X are implied. -b Extract files into basenames so that files with absolute path names are put into the current directory. This option has strange effects when directories are archived. -c Check file size on extraction by counting characters. An error message is reported to the person doing the extraction if the sizes don't match. One reason why the sizes may not match is that shar will append a newline to complete incomplete last lines; shar prints a message that mentions added newlines. Another reason why the sizes may not match is that some network mail programs remove non-whitespace control characters. shar prints a message that mentions control characters to the extractor. -d Use this as the ``end of file'' delimiter instead of the default. The only reason to change it is if you suspect a file contains the default delimiter: SHAR_EOF. -m Reset the exact protection modes of files when they are extracted (using the chmod program). By default, the extractor's default file modes are used, and executable files (e.g., shell scripts) are made executable. -p Use this as the prefix to each line of the archived files. This is to make sure that special characters at the start of lines are not eaten up by programs like mailers. If this option is used, the files will be extracted with the stream editor sed rather than cat so it is more efficient and portable to avoid setting the prefix, though perhaps less safe if you don't know what is in the files. -s Silent running. All checking and extra output is inhibited. -u Archive the input files with the uuencode format for later extraction with uudecode. This will allow you to send files with control characters in them, but will slow down the extracting. You must be sure that the receiving party has access to uudecode. -v Print verbose feedback messages about what shar is doing to be printed during extraction. Sizes of plain files are echoed to allow a simple validity check. SEE ALSO
sh(1), tar(1), cpio(1), tp(1), uuencode(1), uudecode(1) fpack(1) is a plain-file packer useful for UNIX and MSDOS AUTHOR
Gary Perlman (based on a shell version by James Gosling, with additions motivated by many people on the UNIX network: Derek Zahn, Michael Thompson, H. Morrow Long, Fred Avolio, Gran Uddeborg, Chuck Wegrzyn, nucleus!randy@TORONTO, & Bill McKeeman) LIMITATIONS
shar does not know anything about links between files. UNIX User's Manual March 4, 1986 SHAR(1net)
All times are GMT -4. The time now is 05:35 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy