Basic help Post: 302952972

Sponsored Content

Top Forums UNIX for Dummies Questions & Answers Basic help Post 302952972 by bakunin on Monday 24th of August 2015 04:13:38 PM

08-24-2015

Registered User

Most has already been said, but:

`command` and $(command) does basically the same. It executes "command" and uses the output of this command to complete the command line. "command" could either be a single command or even a series of commands, a pipeline, etc..

Example:

Code:

command1 $(command2)

will first execute "command2", then put its output onto the commandline and execute the resulting line. Suppose the output to be "hello world" the shell would try to execute

Code:

command1 "hello world"

after completing "command2". The mechanism is called "process substitution".

The first variant is deprecated, has a lot of shortcomings and should be avoided. Use the second variant instead whenever possible.

Only very old shells (the original Bourne shell for instance) support the first variant(called "backticks") only. Modern shells (ksh, ksh93, bash, ...) support both variants but the former only for backwards compatibility.

I hope this helps.

bakunin

This User Gave Thanks to bakunin For This Post:

bakunin

View Public Profile for bakunin

Find all posts by bakunin

8 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Basic

hi, I am pretty new both to unix and this forum, can anyone help me to give shortcuts to my commands... eg:- instead of "cd /usr/bin" i want to to give " bin " and get to that path. I'm using HP-UX 11.0 abey

2. What is on Your Mind?

Basic...

3. HP-UX

Bt-basic

Hi Guys, I very new to bt-basic even I got 8 years experience on UNIX. I searched through google about bt-basic but nothing really give me solid documentation. Anybody have documentation or manual for this bt-basic? Pls help me

4. UNIX for Dummies Questions & Answers

Need some basic help

Hi everyone, I need some help! I know that this is a very simple little problem but I seem to be stuck. I was just wondering if you could show me the right way. I basicly have to write a single line of commands (using piping) to do the following: From the file data.txt, select all of the...

5. HP-UX

to know the basic

Hi, Good morning I want to install HP-Unix in my PC. I already have windows XP home edition in my PC. I do not want remove XP,But I need HP-Unix in the same system. Is it posssible? If it is what is the name and version of HP-Unix cd? Where can I get the CD to install. I have...

6. UNIX for Dummies Questions & Answers

basic if else

I know this is pretty basic, but i cant figure it out to save my life. i want it to ask for a variable, as long as that variable isnt -/0 i want it to print out the area. else if the variable is -/0, i want it to print out invalid entry. the only problem is it will still try to print out the...

7. Solaris

Basic - how do I?

How do I use ls and grep together to count a certain number of files in a directory? -Thanks

8. What is on Your Mind?

Vs basic

There isn't much of a relation between 80's BASIC and today's BASIC. A lot of languages seem similar. The BASIC I worked with was Dartmouth or VSBASIC. Now existing as ATARI BASIC. PERL and JULIA look appealing, it would be nice if there where a program like VSBASIC. 80's...

LEARN ABOUT DEBIAN

rapt-file

RAPT-FILE(1)															      RAPT-FILE(1)

NAME

       rapt-file - APT package searching utility -- search remotely

SYNOPSIS

       rapt-file [ options ] [ action ] [ pattern ]

DESCRIPTION

       rapt-file  is  a command line tool for searching files in packages for the APT package management system.  It differs from apt-file in that
       it works with remote package indices, so it doesn't need to download full Contents files.

       find   Alias for search.

       list   List the contents of a package matching the pattern pattern. This action is very close to the dpkg -L  command  except  the  package
	      does not need to be installed or fetched.

       search Search in which package a file is included. A list of all packages containing the pattern pattern is returned.

	      rapt-file will only search for filenames, not directory names.  This is due to the format of the Contents files it searches.

       show   Alias for list.

OPTIONS

	  -a, --architecture architecture
	      Sets architecture to architecture. This option is useful if you search a package for a different architecture from the one installed
	      on your system.  It determines how the $ARCH variable in sources.list is expanded (but it does not influence the search in any other
	      way).

	  -l, --package-only
	      Only display package name; do not display file names.

	  -v, --verbose
	      Run rapt-file in verbose mode.

	  -h, --help
	      Display a short help screen.

FILES

       /etc/apt/sources.list
	      Locations to fetch package contents from.

       /etc/apt/sources.list.d/
	      Directory with additional sources.list snippets

AUTHOR

       rapt-file was written by Enrico Zini <enrico@debian.org>.

								     May 2012							      RAPT-FILE(1)