Sponsored Content
Top Forums UNIX for Dummies Questions & Answers Check for difference in output of 2 commands? Post 302489826 by turbofayce on Friday 21st of January 2011 07:12:53 PM
Old 01-21-2011
Mac 10.6.6

(This is just hobby/personal use. I'm on a mac (10.6.6). I have been strictly Windows since 3.1 and I'm trying to get more familiar with what my mac is able to do. I know i'm able to open the terminal app and interface using unix commands, but I don't really know unix at all. I know there's tons of apps for macs to do simple things but are just wasting space and processing so I figured, I might as well learn the OS because that should cover about 90% of those apps. I don't prefer wasting system resources either, so I want to get optimal use out of my system. I really dig apps that use the system properly, and cleverly, rather than rewriting functions to do what's already available thru calling system commands.)

methyl: thanks for the reply. I was playing around with shell scripting trying to figure it out. I was under the impression that I could call unix commands like I would call functions in a oop language, then pipe commands together to get like a variable out of the output, then feed that into some other unix command. Am I looking at this the wrong way?

i.e. in the shell:

command (feed result to) search_for_result_from_previous_command (feed result to) echo_to_standard_output

You can do this sort of thing with unix, right? Because I can imagine endless possibilities with a system like this.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

what's the difference of these two commands?

shouldn't they give the same output? echo `echo \`date\`` is the same as the command date echo `echo date` prints the word date thanks! (3 Replies)
Discussion started by: kfad
3 Replies

2. Solaris

difference between these commands??

Hi, I would like to know what is the difference between executing the mount command in the following ways... eg: /usr/sbin/mount -F <something> AND mount -F <something> I mean , just executing the mount command as opposed to specifying the path and then executing it? ... (3 Replies)
Discussion started by: wrapster
3 Replies

3. UNIX for Dummies Questions & Answers

Difference in commands

Hello All, I have a question about the difference between two commands. I am using Korn and was told by the Unix admin that 'nohup <command> &' equals 'nohup ./<command> &. That there is no difference betwewen the two. Is this true? Also, does the command './<command> &' provide a disconnect... (4 Replies)
Discussion started by: grin1dan
4 Replies

4. Shell Programming and Scripting

Difference in auth key commands?

Good morning! What is the difference between: ssh-keygen -t rsa and ssh-keygen -b 2048 -t rsa? Thanks Bigben (2 Replies)
Discussion started by: bigben1220
2 Replies

5. Shell Programming and Scripting

Difference between the commands

HI all, Please clarify the difference between the following pm2srv:/var/opt/temip/vf/scripts/saiki#awk '{RS = ":"} ; {print $0}' testf2 hey:wasup:howru: Yes I am fine pm2srv:/var/opt/temip/vf/scripts/saiki#awk 'BEGIN { RS = ":" } ; { print $0 }' testf2 hey wasup howru Yes I... (0 Replies)
Discussion started by: saiki
0 Replies

6. Shell Programming and Scripting

Difference between 2 grep - commands

Hi, I need to know the difference between this commands: grep * *search* grep "*" *search* As far as i know does the 2nd command search for files which have a name with *search* and greps then all which have chars from a-z in the file content. But was does the first command?? Best... (1 Reply)
Discussion started by: xus
1 Replies

7. Solaris

Performance difference between commands

Looking at the performance hit on my server, does it matter wich command I run? client # rsh server tar –cf - . | tar –cv –f – or server # tar –cf – . | rsh client ‘cd target && tar –xv -f –‘ I think it doesn't really matter because both command strings involve a tar being run on... (4 Replies)
Discussion started by: petervg
4 Replies

8. AIX

HACMP: difference between 'cl' commands and 'cli' commands

Hi all, I'm new in this forum. I'm looking for the difference between the HACMP commands with the prefix "cl" and "cli". The first type are under /usr/es/sbin/cluster/sbin directory and the second are under /usr/es/sbin/cluster/cspoc directory. I know that the first are called HACMP for AIX... (0 Replies)
Discussion started by: peppix
0 Replies

9. Shell Programming and Scripting

Difference between these cron commands

Hi all I want to make sure I was understanding this correctly if a cron job command was * */20 * * * command does that mean this command will run every 20 hours? also what is the difference between the following two? 0,20,40 * * * * command 20 * * * * command I believe the first... (3 Replies)
Discussion started by: subway69
3 Replies

10. Solaris

Difference between commands

i need to know the difference between two commands ps -ef|grep oracle ps -ef|grep -v grep |grep oracle (1 Reply)
Discussion started by: smazshah
1 Replies
SHELL-QUOTE(1p) 					User Contributed Perl Documentation					   SHELL-QUOTE(1p)

NAME
shell-quote - quote arguments for safe use, unmodified in a shell command SYNOPSIS
shell-quote [switch]... arg... DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands or files with embedded white space or shell globbing characters safely. Here are a few examples. EXAMPLES
ssh preserving args When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and passes them to "$SHELL -c". This doesn't work as intended: ssh host touch 'hi there' # fails It creates 2 files, hi and there. Instead, do this: cmd=`shell-quote touch 'hi there'` ssh host "$cmd" This gives you just 1 file, hi there. process find output It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote: eval set -- `find -type f -print0 | xargs -0 shell-quote --` debug shell scripts shell-quote is better than echo for debugging shell scripts. debug() { [ -z "$debug" ] || shell-quote "debug:" "$@" } With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can. save a command for later shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are things the user can't pass through), you can do something like this: user_switches= while [ $# != 0 ] do case x$1 in x--pass-through) [ $# -gt 1 ] || die "need an argument for $1" user_switches="$user_switches "`shell-quote -- "$2"` shift;; # process other switches esac shift done # later eval "shell-quote some-command $user_switches my args" OPTIONS
--debug Turn debugging on. --help Show the usage message and die. --version Show the version number and exit. AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions. AUTHOR
Roderick Schertler <roderick@argon.org> perl v5.8.4 2005-05-03 SHELL-QUOTE(1p)
All times are GMT -4. The time now is 02:58 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy