Sponsored Content
Full Discussion: Exclamation point in Bash
Top Forums Shell Programming and Scripting Exclamation point in Bash Post 302317551 by Enobarbus37 on Tuesday 19th of May 2009 09:46:51 AM
Old 05-19-2009
Exclamation point in Bash

Here is a script using egrep that extracts the last word in each line:

egrep -o " [a-zA-Z'-]+[,:.!';?]*$" File.txt > Results.txt

If it is placed in a file with the requisite header:

#!/bin/bash

it works perfectly.

If on the other hand, one attempts it from the command line, one gets the following error:

-bash: !': event not found

The problem is the exclamation point in the regexp.

I have tried numerous ways to get it to work from the command line and failed: using single quotes, escaping the !, etc.

Nothing works.

Now, you may ask, if it works from a file, why insist on doing it from the command line? You're right. I shouldn't. And my research indicates that this problem is particularly annoying in bash and that people simply recommend using a different shell.

But can it be solved?

Thanks in advance...
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Floating point numeric comparisions in bash

Hi, I am trying to compare 2 floating point numbers 0.8 and 0.15 using bash and get the largest of the two. Can anyone advise. (2 Replies)
Discussion started by: borncrazy
2 Replies

2. Shell Programming and Scripting

BASH: floating point exception

Hi, guys, today, I have copied a simple script which runs correctly on a computer to another one. But, the latter informs me: Floating point exception! @ ./command_module a b c where command_module is the module compiled by myself. So, I have fixed it by following steps: 1.... (5 Replies)
Discussion started by: mapleleaves
5 Replies

3. Shell Programming and Scripting

floating point not recognized by printf in bash

Dear all, I have the following question. Let's say that I have the following script #!/bin/bash value=0.4987865 a=` printf "%6.2f" $value ` b=`echo $value + $value | bc -l` echo $a echo $b exit And the exit is: 0,00 .9975730 Thus, the problem is that the printf order does not... (2 Replies)
Discussion started by: josegr
2 Replies

4. Shell Programming and Scripting

Bash take word after specific point and till next space?

Hello, I have an output like Interface Chipset Driver wlan0 Intel 4965/5xxx iwlagn - and I want to take only the 'wlan0' string. This can be done by a="Interface Chipset Driver wlan0 Intel 4965/5xxx iwlagn - " b=${a:25:6} echo $bThe thing is that wlan0 can be something else, like eth0 or... (2 Replies)
Discussion started by: hakermania
2 Replies

5. Shell Programming and Scripting

[BASH] Regex for floating point number

Hey again, I have a basic regex that tests if a number is a float. Thank you. (5 Replies)
Discussion started by: whyte_rhyno
5 Replies

6. UNIX for Advanced & Expert Users

explanation point bash

What is the deal with explanation point in bash? I thought only dollar sign ($), the back-tick (`) and the backslash (\) were special in double quotes. Can someone please explain what is going on here? Why do I have to use single quotes or backslash the "!"? $ vlc "/media/Part... (4 Replies)
Discussion started by: cokedude
4 Replies

7. Shell Programming and Scripting

Bash Floating point math with bc

Hello Everyone, I am currently working on a script to calculate optimal tcp window size the formula that I am following is 2 x (bandwith speed /8 * Round Trip Time ) = x This is what I have so far #!/bin/bash echo "Enter connection speed" << Get the speed of the Connection from... (3 Replies)
Discussion started by: bmfmancini
3 Replies

8. Shell Programming and Scripting

[BASH] Floating point exception

Heyas I have a script (vhs - video handler script, using ffmpeg) to encode videos. It also encodes a dvd, but until now just non-copy-protected ones, so i've tried to add/implement a vobcopy wrapper to be used by my script. At first it looked quite fine, but when changing from the first VOB... (9 Replies)
Discussion started by: sea
9 Replies

9. Shell Programming and Scripting

Bash script to print the smallest floating point number in a row that is not 0

Hello, I have often found bash to be difficult when it comes to floating point numbers. I have data with rows of tab delimited floating point numbers. I need to find the smallest number in each row that is not 0.0. Numbers can be negative and they do not come in any particular order for a given... (9 Replies)
Discussion started by: LMHmedchem
9 Replies

10. Shell Programming and Scripting

Comparison of floating point numbers in bash

I have the following code snippet in bash if ]; then minm=`echo "$diff" | bc` fi It works well for most of the cases. However lets say diff is -0.17 and minm is -0.0017. In such a case the comparison seems to fail. Is the correct way to compare a mixture of positive and... (12 Replies)
Discussion started by: ngabrani
12 Replies
RBASH(1)						      General Commands Manual							  RBASH(1)

NAME
rbash - restricted bash, see bash(1) RESTRICTED SHELL
If bash is started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted. A restricted shell is used to set up an environment more controlled than the standard shell. It behaves identically to bash with the exception that the follow- ing are disallowed or not performed: o changing directories with cd o setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV o specifying command names containing / o specifying a file name containing a / as an argument to the . builtin command o specifying a filename containing a slash as an argument to the -p option to the hash builtin command o importing function definitions from the shell environment at startup o parsing the value of SHELLOPTS from the shell environment at startup o redirecting output using the >, >|, <>, >&, &>, and >> redirection operators o using the exec builtin command to replace the shell with another command o adding or deleting builtin commands with the -f and -d options to the enable builtin command o using the enable builtin command to enable disabled shell builtins o specifying the -p option to the command builtin command o turning off restricted mode with set +r or set +o restricted. These restrictions are enforced after any startup files are read. When a command that is found to be a shell script is executed, rbash turns off any restrictions in the shell spawned to execute the script. SEE ALSO
bash(1) GNU Bash-4.0 2004 Apr 20 RBASH(1)
All times are GMT -4. The time now is 03:55 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy