Sponsored Content
Top Forums Shell Programming and Scripting On how to select the right tool for a given task Post 302248046 by cfajohnson on Friday 17th of October 2008 12:37:29 AM
Old 10-17-2008
Quote:
Originally Posted by ghostdog74
i understand where you are coming from. but there are few situations i can think of that using shell provided internals are not suitable
1) writing portable scripts. The syntax that you use for string manipulations in bash for example, is not universal for every shell

The techniques I used are part of the standard UNIX shell.

They are portable to all modern *nix systems (and many older ones).

I used nothing that is bash specific.
Quote:
2) doing more complex string manipulation like grouped pattern matches.

When a regular expression, rather than wildcard expansion is necessary, then sed might be appropriate (though I would usually prefer awk).
Quote:
3) and of course, using sed to go over files can be faster than using pure shell constructs.

As I said, sed is for working with files.
 

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

process vs task

Hi, I am new to this forum and unix too. I have just started learning unix. As I was going through the first chapter, I read that unix is multitasking, multiprogramming, multiprocessing and multiuser OS. My question is: Is there any difference between a TASK and a PROCESS. How are PROCESS... (2 Replies)
Discussion started by: hana
2 Replies

2. Shell Programming and Scripting

comment and Uncomment single task out of multiple task

I have a file contains TASK gsnmpproxy { CommandLine = $SMCHOME/bin/gsnmpProxy.exe } TASK gsnmpdbgui { CommandLine = $SMCHOME/bin/gsnmpdbgui.exe I would like to comment and than uncomment specific task eg TASK gsnmpproxy Pls suggest how to do in shell script (9 Replies)
Discussion started by: madhusmita
9 Replies

3. Shell Programming and Scripting

Parse an XML task list to create each task.xml file

I have an task definition listing xml file that contains a list of tasks such as <TASKLIST <TASK definition="Completion date" id="Taskname1" Some other <CODE name="Code12" <Parameter pname="Dog" input="5.6" units="feet" etc /Parameter> <Parameter... (3 Replies)
Discussion started by: MissI
3 Replies

4. Programming

Help with task daemon

believe it or not but this is my first c program (i've worked with java, C#, php though) I am trying to make a daemon that checks if mplayer is running(it's for a projection room) and if it is not then to run mplayer with a file.. So far it's not working and I don't know why Help and comments... (5 Replies)
Discussion started by: james2432
5 Replies

5. Boot Loaders

Reboot and Select Proper Boot device or insert Boot media in select Boot device and press a key

Hello, I have kubuntu on my laptop and now I decided to switch to Windows 7. I made the bios settings properly (first choice is boot from cd\vd) but I see the error " reboot and select proper Boot device or insert Boot media in select Boot device and press a key " I have tried CD and... (0 Replies)
Discussion started by: rpf
0 Replies

6. Shell Programming and Scripting

last task for my script

hi, infile- create table salary ( occupation_code char(40), earnings decimal(10,2), occ_yearend integer ); outfile- salary:create table salary salary:( occupation_code char(40), salary: earnings decimal(10,2), salary: occ_yearend integer salary:); Thanks. (4 Replies)
Discussion started by: dvah
4 Replies

7. Shell Programming and Scripting

task

Hi all, I'm newbie and stuck here. Thanks for any help. Input(txt file) a b X c d Y e f Z g h W Requested output: a b X Y c d Y X e f Z W g h W Z Please use code tags when posting data and code samples! (10 Replies)
Discussion started by: hernand
10 Replies

8. Shell Programming and Scripting

Task

Hi experts, I have a problem with the below shell task: I need to modify the file creatin a paired row , per each row which matches filter (e.g. number of nonempty columns = 5) Output should look like this: second row is original one from the input, first row(red) is pairing row, it's... (29 Replies)
Discussion started by: hernand
29 Replies

9. Homework & Coursework Questions

[HELP] Easy task

I have a simple task for my school work. I'm new with unix, so i need help. I need to write a scenario. Task is. From created txt file read first 3 words and create a 3 catalogs with those 3 words. 2 of those new catalogs should be transferred to other directory. If someone could help me just... (1 Reply)
Discussion started by: justynykas
1 Replies
SHELL-QUOTE(1)						User Contributed Perl Documentation					    SHELL-QUOTE(1)

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 v5.16.3 2010-06-11 SHELL-QUOTE(1)
All times are GMT -4. The time now is 01:57 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy