Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Command behaves different in script and on prompt
Operating Systems AIX Command behaves different in script and on prompt Post 302445880 by bakunin on Tuesday 17th of August 2010 05:49:16 AM
Old 08-17-2010
Quote:
Originally Posted by panchpan
Code:
input=`head -1 /tmp/tuxob.lst | awk '{print $NF}'`

If above is the script, then how do I put if conditions. i.e. If $input = '*****' do something.
First off, you don't need any if-contructions. You should quote your variables regardless of them containing something which has to be quoted or not, because even if said variables normally don't have a content which has to be quoted they might do so occasionally and a script shouldn't work "most of the times", but always.

In programming caution sometimes helps but never hurts, so be as cautious as possible.

Secondly, you shouldn't use the backticks any more: they are supported only for backwards compatibility purposes. Use the "$(...)" instead:

Code:
input="$(head -1 /tmp/tuxob.lst | awk '{print $NF}')"

Thirdly, the command only fills a variable with some content - in this case some asterisks. No shell expansion is done here. It is probably done when you subsequently try to display the variables contents. THIS is the place where you have to protect your variable from being expanded by the shell:

Code:
input="$(head -1 /tmp/tuxob.lst | awk '{print $NF}')"
echo $input         # will be expanded
echo "$input"       # will not be expanded

Btw.: if the only thing you want to do is to display it, you don't even need the variable:

Code:
echo "$(head -1 /tmp/tuxob.lst | awk '{print $NF}')"  # will not be expanded
echo $(head -1 /tmp/tuxob.lst | awk '{print $NF}')    # will be expanded

I hope this helps.

bakunin
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Command prompt from within a script?

I am writing a menu script and one of the options is to access a Command Prompt and return to the menu via CTRL-D. I have tried using a loop and echoing the PS1 value, then using read to assign whatever is entered into a variable, then executing the value of that variable as a command using .... (1 Reply)
Discussion started by: sanitywonko
1 Replies

2. Shell Programming and Scripting

Why Does Command Run From Prompt But Not From Script?

I hope someone can shed any light on this mystery. I am trying to run the following command: su userID -c remsh server -l userid -n "awk -F^ '\$4 == \"SMITH\"' /tmp/infromational/version74b/LIVE/TEMPORARY/ABCfiles/HLC_Database_File.bat|head -1" > /tmp/variant/45BV32/var/store13.logfnd I... (15 Replies)
Discussion started by: Korn0474
15 Replies

3. Shell Programming and Scripting

Script behaves different when run from cron vs. manually

Hey all, Just wanted to get some input on a script I am using to import files into a MySQL database. The process is pretty simple: my main server exports these files and FTPs them. I have a script that FTPs them to the machine running that runs this script. The FTP script runs without issue... (2 Replies)
Discussion started by: billtwild
2 Replies

4. Windows & DOS: Issues & Discussions

Awk script in DOS and Linux behaves differently :(

Hi, I have an awk script which performs simple operations of variable assignments and finally printing the variables in custom form. BEGIN {FS=OFS="\n"} { v1=substr($0,1,15) v2=substr($0,16,200) v3=substr($0,216,20) print v1 "|" v2 "|" v3 } The input file being processed... (2 Replies)
Discussion started by: vidyak
2 Replies

5. UNIX for Dummies Questions & Answers

running command prompt executable file in shell script

hi i have file extentioned with test.vbs. i am able to run this file n execute through command promt but i dont know how to run in shell script example: file name is test.vbs which contains strSoundFile = "C:\windows\Media\Notify.wav" Set objShell = CreateObject("Wscript.Shell") strCommand... (5 Replies)
Discussion started by: atl@mav
5 Replies

6. Shell Programming and Scripting

script submitted using ssh does not return to command prompt

Gurus, I have written a shell script to backup a database and applications. This is how the script works: 1. As applications user (say applmgr), the main backup script, say backup.sh, is kicked off. 2. backup.sh does ssh to oracle user and kicks off the database backup using nohup and... (1 Reply)
Discussion started by: sunpraveen
1 Replies

7. Shell Programming and Scripting

Executing a script from CRON behaves differently than terminal

Hi have a script which transferers from Microsoft server to Linux box. The scripts(ksh) is on Linux box. If I run script from terminal, it transfers files to directory. Where as If I run script from CRON. It does not. Here is the log of both: Terminal execution log:... (2 Replies)
Discussion started by: dipeshvshah
2 Replies

8. Shell Programming and Scripting

su - user -c 'command' behaves differently

I notice that su - user (note with dash) brings in more of the user's environment than does su - user -c 'command'. For example, if root does an su - user, and types "umask" to the prompt, one umask is displayed; yet, if instead the command is su - user -c 'umask', the value is different. I thought... (2 Replies)
Discussion started by: drokerm
2 Replies

9. Shell Programming and Scripting

awk command in script gives error while same awk command at prompt runs fine: Why?

Hello all, Here is what my bash script does: sums number columns, saves the tot in new column, outputs if tot >= threshold val: > cat getnon0file.sh #!/bin/bash this="getnon0file.sh" USAGE=$this" InFile="xyz.38" Min="0.05" # awk '{sum=0; for(n=2; n<=NF; n++){sum+=$n};... (4 Replies)
Discussion started by: catalys
4 Replies

10. UNIX for Dummies Questions & Answers

Shell script not working but command works in command prompt

Hi everyone I have a problem with my script If I try directly this command /usr/bin/nice -n 19 mysqldump -u root --password="******" wiki_schneider -c | nice -n 19 gzip -9 > /point_de_montage/$(date '+%Y%m%d')-wiki-db.sql.gz It works But if I simply add this command in a script and... (8 Replies)
Discussion started by: picemma
8 Replies

LEARN ABOUT DEBIAN

irsend

IRSEND(1)							   User Commands							 IRSEND(1)

NAME

       irsend - basic LIRC program to send infra-red commands

SYNOPSIS

       irsend [options] DIRECTIVE REMOTE CODE [CODE...]

DESCRIPTION

       Asks the lircd daemon to send one or more CIR (Consumer Infra-Red) commands. This is intended for remote control of electronic devices such
       as TV boxes, HiFi sets, etc.

       DIRECTIVE can be:
	  SEND_ONCE	    - send CODE [CODE ...] once
	  SEND_START	    - start repeating CODE
	  SEND_STOP	    - stop repeating CODE
	  LIST		    - list configured remote items
	  SET_TRANSMITTERS  - set transmitters NUM [NUM ...]
	  SIMULATE	    - simulate IR event

       REMOTE is the name of a remote, as described in the lircd configuration file.

       CODE is the name of a remote control key of REMOTE, as it appears in the lircd configuration file.

       NUM is the transmitter number of the hardware device.

       For the LIST DIRECTIVE, REMOTE and/or CODE can be empty:

	  LIST	 ""    ""   - list all configured remote names
	  LIST REMOTE  ""   - list all codes of REMOTE
	  LIST REMOTE CODE  - list only CODE of REMOTE

       The SIMULATE command only works if it has been explicitly enabled in lircd.

       -h --help
	      display usage summary

       -v --version
	      display version

       -d --device
	      use given lircd socket [/var/run/lirc/lircd]

       -a --address=host[:port]
	      connect to lircd at this address

       -# --count=n
	      send command n times

EXAMPLES

	  irsend LIST DenonTuner ""
	  irsend SEND_ONCE  DenonTuner PROG-SCAN
	  irsend SEND_ONCE  OnkyoAmpli VOL-UP VOL-UP VOL-UP VOL-UP
	  irsend SEND_START OnkyoAmpli VOL-DOWN ; sleep 3
	  irsend SEND_STOP  OnkyoAmpli VOL-DOWN
	  irsend SET_TRANSMITTERS 1
	  irsend SET_TRANSMITTERS 1 3 4
	  irsend SIMULATE "0000000000000476 00 OK TECHNISAT_ST3004S"

FILES

       /etc/lirc/lircd.conf
	      Default lircd configuration file.  It should contain all the remotes, their infra-red codes and the corresponding timing	and  wave-
	      form details.

DIAGNOSTICS

       If lircd is not running (or /var/run/lirc/lircd lacks write permissions) irsend aborts with the following diagnostics:
       "irsend: could not connect to socket"
       "irsend: Connection refused" (or "Permission denied").

SEE ALSO

       The documentation for lirc is maintained as html pages. They are located under html/ in the documentation directory.

       lircd(8), mode2(1), smode2(1), xmode2(1), irrecord(1), irw(1), http://www.lirc.org.

irsend 0.9.0-pre1						   October 2010 							 IRSEND(1)
All times are GMT -4. The time now is 03:43 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy