grep a variable


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting grep a variable
# 1  
Old 04-27-2009
grep a variable

can i grep a variable
say i have a variable var=`hostname` and I want to make an if statement like
if grep "esp-ueh" $var;then......
how can i do this
I dont want to store this variable in a file and the grep it because my script will be used at the same time on multiple stations and then that file will keep getting overwritten.
# 2  
Old 04-27-2009
var=`hostname`
if [[ `grep -c "esp-ueh" $var ` > 0 ]]; then
echo "exits"
else
echo "does not exists"
fi


cheers,
Devaraj Takhellambam
# 3  
Old 04-27-2009
PHP

you can do that...var=$(...your command...) | grep "esp-ueh"if you want testif [ var="esp-ueh" ] then;...
# 4  
Old 04-27-2009
protocomm does the command have to be in `command` for it to work coz when i echo $var it is empty
# 5  
Old 04-27-2009
devtak the code doent seem to work.it always prints "does not exists"
# 6  
Old 04-27-2009
devtak this is the error that i get
grep: esp-ueh32: No such file or directory
does not exist
# 7  
Old 04-27-2009
Hammer & Screwdriver your variable is empty?

set a variable
Code:
> myvar=alpha123

an exact way to show whats in a variable
Code:
> echo "${myvar}"
alpha123

show that ASCII values - each of those numbers is the ASCII representation of the characters. 97 is an 'a', 108 is 'l', and so on. the final 10 is code for a LF (line feed) terminator.
Code:
> echo "${myvar}" | od -An -t dC -w10
   97  108  112  104   97   49   50   51   10

Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

How to use $variable in grep?

hi i have a file which contains some messages counters. below is the snippet on the file. 17-05-29::22:36:21|message|231 17-05-29::22:36:31|message|222 17-05-29::22:36:41|message|213 17-05-30::22:36:51|message|221 17-05-30::22:37:01|message|227 17-05-30::22:37:11|message|207... (5 Replies)
Discussion started by: scriptor
5 Replies

2. Shell Programming and Scripting

Help grep one variable over other

Hi, I am trying to grep one variable over the other variable Example: i=abc j=ab grep $j $i I am getting this error: The error is due to $i being variable and not file. I know I could do it by putting the value of abc in a file and then greping it. (1 Reply)
Discussion started by: pinnacle
1 Replies

3. Shell Programming and Scripting

grep variable

I've got a file that I'm trying to grep through that looks like this: alpha1 alpha2 alpha3 beta1 beta2 gamma5 gamma6 gamma7 gamma8 gamma9 and I want the output to only contain the line with the highest value for each, so the output I want is: alpha3 beta2 gamma9 I also need... (11 Replies)
Discussion started by: tiberione
11 Replies

4. Shell Programming and Scripting

grep in a variable

Hello, I usually search extensively and have to date found what I've needed. However, this one's got me stumped. I need to create a variable as follow. The issue however is that upon execution, it freezes. $var1 isn't always present in usage.log and this is fine but I'd like it to continue with... (6 Replies)
Discussion started by: shadyuk
6 Replies

5. Shell Programming and Scripting

grep using variable

I have a pattern like: column "5" is missing PS: the no is in double quotes. The number usally changes, so we use a loop to grep. grep 'column "$number" is missing' filename.txt But it is not working.... How to solve this? (2 Replies)
Discussion started by: karumudi7
2 Replies

6. Shell Programming and Scripting

Grep through a variable

I want to search a text in file but that file is pointing to variable. ex: file=there was nothing special grep "there was nothing" $file but its not working . Can u let me know that how we can use variable($file) in grep command. Please use code tags (6 Replies)
Discussion started by: allthanksquery
6 Replies

7. Shell Programming and Scripting

grep using variable

how can I use grep with a variable to find a value? cat data.out Hello World grep "Hello World" data.out Hello World ## Value found I want to do something like this but can't seem to get it to work any suggestions would be appreciated. var="Hello World" grep $var data.out (3 Replies)
Discussion started by: BeefStu
3 Replies

8. Shell Programming and Scripting

grep a variable

Hi all, I am trying to do a simple thing in my mind. However I am fairly new to bash. What I need to do is create a folder for each partition on each CD, and each partition has a unique name (with spaces in it, do not ask why, it is already done :confused: ) . All CD's will show up... (2 Replies)
Discussion started by: sgstuart
2 Replies

9. Shell Programming and Scripting

grep with variable

Hi, I can't get this script to work (returns 0, should return 3): $ cat A.lst | \ while read LINE do echo "$LINE" grep -c "$LINE" B.tmp done> > > > > Socket 0 $ but in contrast this one works fine (returns 3 as expected): $ LINE=Socket $ grep -c $LINE B.tmp 3 $ (5 Replies)
Discussion started by: ozvena
5 Replies

10. Shell Programming and Scripting

How to grep a variable?

Hi, I'd like to grep a variable that I saved in the program. Like grep '0\$variable1' file1 Does someone know what's wrong with this command? Thanks a lot! (2 Replies)
Discussion started by: whatisthis
2 Replies
Login or Register to Ask a Question