Sponsored Content
Top Forums Shell Programming and Scripting Implementing MORE,HEAD & TAIL Post 55768 by zazzybob on Sunday 19th of September 2004 04:22:59 PM
Old 09-19-2004
Unless you actually want to rewrite the commands in C, you'll be hard pushed to get all of the required funcitonality using shell scripts...

You can use a simple " sed -n '1,10p' foofile " to print the first 10 lines of foofile, (thus mimicking "head foofile") but why would you want to reimplement this? (Unless of course, you are trying to further your programming knowledge)

Cheers
ZB
 

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

head & tail

I've a major file which includes other files and now I wanna 'cut' the file in several minor parts....like .... find / -name "*.tmp" >filea wc -l filea >fileb sed -e '1s/ filea//' fileb >filec AMOUNT=`cat filec` if ; then cat file a |head -100l (ell) |tail -100l >filec cat file a |head... (6 Replies)
Discussion started by: svennie
6 Replies

2. Shell Programming and Scripting

Head and Tail in One Line

I am new to UNIX......I have one file which contains thousnads of records with header and tailer. Header Record 1 Record 2 .... .... Last Record Trailer I want to concatenate Header and Trailer in the first line....now the output should look like this: Header: Header value, Trailer:... (2 Replies)
Discussion started by: 33junaid
2 Replies

3. Shell Programming and Scripting

Imitate head and tail command script

Hi, I have been given assignment of 30 scripts out of which I was able to solve many, I need help with few out of which one asks to imitate head and tail command of unix without using the head and tail commands. Problem is stated below: Write an interactive shell script to imitate the head... (5 Replies)
Discussion started by: nutalk
5 Replies

4. Shell Programming and Scripting

Averaging in increments using awk & head/tail

Hi, I only have a very limited understanding and experience with writing code and I was hoping I could get some help. I have a dataset of two columns (txt format, numbers in each row separated by a tab) Eg. 1 5 2 5 3 6 4 7 5 6 6 6 7 ... (5 Replies)
Discussion started by: Emred_Skye
5 Replies

5. Shell Programming and Scripting

head / tail combination returns multiple rows

Hi, As part of our project, we need to load historical data for a year before our system is live. We have the data feed files that we need to load. However, I need to make sure that the file structure (number of fields separated by a comma) on the field is same for all the files of the same... (1 Reply)
Discussion started by: raj.jha
1 Replies

6. UNIX for Dummies Questions & Answers

head\tail how to display middle lines

hay i need to display middle line: 1 2 3 4 5 how can i display 3-4? (6 Replies)
Discussion started by: margan_ron
6 Replies

7. Homework & Coursework Questions

Head Tail Problem

Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted! 1. The problem statement, all variables and given/known data: view the 7th line of the program xxx.sh 2. Relevant commands, code, scripts, algorithms: head command tail... (10 Replies)
Discussion started by: hbell221
10 Replies

8. UNIX for Dummies Questions & Answers

What should be precedence of using awk, sed, head and tail in UNIX?

Hi All, I am new to unix. In this forum some days back, I have read something like below: 1) Do not use perl if awk can do your work. 2) Do not use awk if sed can do your work. . . . I do not re-collect the whole thing. I think it is good to know the precedence of using these... (2 Replies)
Discussion started by: Prathmesh
2 Replies

9. Homework & Coursework Questions

How to display certain line of file only using head or tail in 1 command?

First month learning about the Linux terminal and it has been a challenge yet fun so far. We're learning by using a gameshell. I'm trying to display a certain line ( only allowed 1 command ) from a file only using the head or tail. I'm pretty about this answer: head -23 history.txt | tail -1... (1 Reply)
Discussion started by: forzatekk
1 Replies
Path::Class(3)						User Contributed Perl Documentation					    Path::Class(3)

NAME
Path::Class - Cross-platform path specification manipulation VERSION
version 0.33 SYNOPSIS
use Path::Class; my $dir = dir('foo', 'bar'); # Path::Class::Dir object my $file = file('bob', 'file.txt'); # Path::Class::File object # Stringifies to 'foo/bar' on Unix, 'fooar' on Windows, etc. print "dir: $dir "; # Stringifies to 'bob/file.txt' on Unix, 'bobfile.txt' on Windows print "file: $file "; my $subdir = $dir->subdir('baz'); # foo/bar/baz my $parent = $subdir->parent; # foo/bar my $parent2 = $parent->parent; # foo my $dir2 = $file->dir; # bob # Work with foreign paths use Path::Class qw(foreign_file foreign_dir); my $file = foreign_file('Mac', ':foo:file.txt'); print $file->dir; # :foo: print $file->as_foreign('Win32'); # foofile.txt # Interact with the underlying filesystem: # $dir_handle is an IO::Dir object my $dir_handle = $dir->open or die "Can't read $dir: $!"; # $file_handle is an IO::File object my $file_handle = $file->open($mode) or die "Can't read $file: $!"; DESCRIPTION
"Path::Class" is a module for manipulation of file and directory specifications (strings describing their locations, like '/home/ken/foo.txt' or 'C:WindowsFoo.txt') in a cross-platform manner. It supports pretty much every platform Perl runs on, including Unix, Windows, Mac, VMS, Epoc, Cygwin, OS/2, and NetWare. The well-known module File::Spec also provides this service, but it's sort of awkward to use well, so people sometimes avoid it, or use it in a way that won't actually work properly on platforms significantly different than the ones they've tested their code on. In fact, "Path::Class" uses "File::Spec" internally, wrapping all the unsightly details so you can concentrate on your application code. Whereas "File::Spec" provides functions for some common path manipulations, "Path::Class" provides an object-oriented model of the world of path specifications and their underlying semantics. "File::Spec" doesn't create any objects, and its classes represent the different ways in which paths must be manipulated on various platforms (not a very intuitive concept). "Path::Class" creates objects representing files and directories, and provides methods that relate them to each other. For instance, the following "File::Spec" code: my $absolute = File::Spec->file_name_is_absolute( File::Spec->catfile( @dirs, $file ) ); can be written using "Path::Class" as my $absolute = Path::Class::File->new( @dirs, $file )->is_absolute; or even as my $absolute = file( @dirs, $file )->is_absolute; Similar readability improvements should happen all over the place when using "Path::Class". Using "Path::Class" can help solve real problems in your code too - for instance, how many people actually take the "volume" (like "C:" on Windows) into account when writing "File::Spec"-using code? I thought not. But if you use "Path::Class", your file and directory objects will know what volumes they refer to and do the right thing. The guts of the "Path::Class" code live in the Path::Class::File and Path::Class::Dir modules, so please see those modules' documentation for more details about how to use them. EXPORT The following functions are exported by default. file A synonym for "Path::Class::File->new". dir A synonym for "Path::Class::Dir->new". If you would like to prevent their export, you may explicitly pass an empty list to perl's "use", i.e. "use Path::Class ()". The following are exported only on demand. foreign_file A synonym for "Path::Class::File->new_foreign". foreign_dir A synonym for "Path::Class::Dir->new_foreign". tempdir Create a new Path::Class::Dir instance pointed to temporary directory. my $temp = Path::Class::tempdir(CLEANUP => 1); A synonym for "Path::Class::Dir->new(File::Temp::tempdir(@_))". Notes on Cross-Platform Compatibility Although it is much easier to write cross-platform-friendly code with this module than with "File::Spec", there are still some issues to be aware of. o On some platforms, notably VMS and some older versions of DOS (I think), all filenames must have an extension. Thus if you create a file called foo/bar and then ask for a list of files in the directory foo, you may find a file called bar. instead of the bar you were expecting. Thus it might be a good idea to use an extension in the first place. AUTHOR
Ken Williams, KWILLIAMS@cpan.org COPYRIGHT
Copyright (c) Ken Williams. All rights reserved. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. SEE ALSO
Path::Class::Dir, Path::Class::File, File::Spec perl v5.18.2 2017-10-06 Path::Class(3)
All times are GMT -4. The time now is 01:56 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy