Sponsored Content
Top Forums UNIX for Advanced & Expert Users [Discussion] POSIX, the Love of Backticks and All That Jazz Post 302990486 by MichaelFelt on Friday 27th of January 2017 03:28:32 AM
Old 01-27-2017
Quote:
Originally Posted by bakunin
Hmm, 20 years of using ksh and i didn't know that. That is embarrassing.

bakunin
Don't be. I have 38+ years on UNIX and I still use \ - because often - first I am assigning the "command" to a variable (as the string) and later am executing it (the variable). Same as I (must) do in files like configure.{ac|in}, Makefile, etc..

In short - better one \ too many that one short.
 

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Perl - backticks v system in if statements

Can someone explain the difference between backticks and system when evaluated in these if statements: sub getDate { print "start date\n"; if ( system("/bin/date") ) { print "can't get date\n"; exit(2); } print "finish date\n"; } Returns the following: start date Thu... (5 Replies)
Discussion started by: gjkeenan
5 Replies

2. Shell Programming and Scripting

Backticks within backticks?

Hi, I'm trying to do something like this: range= `expr `date '+%m'` - 1` and it does not work. How can I tell it to evaluate an expression within another expression evaluation? I was at first worried that `date '+%m'` would return a string but apparently expr does the math okay normally, so the... (3 Replies)
Discussion started by: jeriryan87
3 Replies

3. UNIX for Dummies Questions & Answers

sed: removing backticks from certain lines

Hi, I would like to change some lines in my mysql-dump, because there a syntax problems with some version of mysql. I 'd like to change USE ´someDatabase´; to USE someDatabase; (without backticks) using the sed command in the shell Thanks & best regards Bernd (5 Replies)
Discussion started by: bjb
5 Replies

4. Shell Programming and Scripting

Am I abusing backticks?

I'm always concerned I might be abusing backticks within my scripts. A current script I'm writing has this for example: stripscriptname=`echo $scriptname | sed 's/\(.*\)\..*/\1/'` stripsearch=`echo $searchpattern | tr -d ' ,/'` Both of these variables are set inside the script (in fact,... (2 Replies)
Discussion started by: mglenney
2 Replies

5. Shell Programming and Scripting

Difference between using xargs and backticks

Hey all. Just a fast question, what is the technical difference between using back ticks and using xargs to perform a command? Here's an example Find /mydir -name *.conf |xargs rm Vs Rm 'find /mydir -name *.conf' Is there a performance hit? I know they do the same thing but which is... (1 Reply)
Discussion started by: msarro
1 Replies

6. Red Hat

perl backticks: can't redirect output.

Hi everyone. This is a bit of a perl/linux mixed question. I am trying to redirect STDOUT of chsh by using the following line of perl code. system ("chsh -s /sbin/nologin $testing 1>/dev/null"); This should redirect STDOUT to /dev/null but it won't do that for some odd reason. Any ideas or... (6 Replies)
Discussion started by: austinharris43
6 Replies

7. Shell Programming and Scripting

Help with remove backticks in a text file

Input file: 'data_1' 'data_10' 'data1311' '235data_13' Desired output: data_1 data_10 data1311 235data_13 Can I know how to remove back tick"'" in a file? Many thanks for advice. (3 Replies)
Discussion started by: perl_beginner
3 Replies

8. Shell Programming and Scripting

SSH and Backticks [solved]

I have been testing a new script and cannot figure out why my `cat spath` will not execute on the remote machine? sudo ssh -p 22344 -o "PasswordAuthentication no" -o "HostbasedAuthentication yes" -l testuser 192.168.1.6 "find `cat spath` -depth" cat: spath: No such file or directory but... (0 Replies)
Discussion started by: metallica1973
0 Replies

9. Shell Programming and Scripting

Nesting backticks

I'm trying to make a dialog window that prints the output of grep that takes the output of find. Unfortunately my nested backticks don't work. Here is the dialog window: dialog --stdout --title "test" --backtitle "test" --msgbox "Test:\n `grep -l "${tablica}" `find $string``" 16 60I think I... (2 Replies)
Discussion started by: Starting_Leaf
2 Replies
shift(1)							   User Commands							  shift(1)

NAME
shift - shell built-in function to traverse either a shell's argument list or a list of field-separated words SYNOPSIS
sh shift [n] csh shift [variable] ksh * shift [n] DESCRIPTION
sh The positional parameters from $n+1 ... are renamed $1 ... . If n is not given, it is assumed to be 1. csh The components of argv, or variable, if supplied, are shifted to the left, discarding the first component. It is an error for the variable not to be set or to have a null value. ksh The positional parameters from $n+1 $n+1 ... are renamed $1 ..., default n is 1. The parameter n can be any arithmetic expression that evaluates to a non-negative number less than or equal to $#. On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways: 1. Variable assignment lists preceding the command remain in effect when the command completes. 2. I/O redirections are processed after variable assignments. 3. Errors cause a script that contains them to abort. 4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari- able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not performed. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
csh(1), ksh(1), sh(1), attributes(5) SunOS 5.10 15 Apr 1994 shift(1)
All times are GMT -4. The time now is 01:54 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy