Shell Programming and Scripting

Take example of below file.

abc.txt

Code:

nas1:/abc/test/test1                /test
nas1:/abc/test/test1/test2       /test/abc
nas1:/abc/test/

Now i have a variable that contains "nas1:/abc/test/test1" value , so i need to search the above file for this variable and print only this line.

output expected :-
nas1:/abc/test/test1 /test


i tried cat abc.txt | grep -w "nas1:/abc/test/test1 " , its not working for few linux servers , so can i have some commands that can run on all distros.

Hello mohit_vardhani,

You could use simple grepoption as follows.

Code:

grep "nas1:/abc/test/test1"  Input_file

But having said that, above code will give those lines also which have some more text after this line too like above code's output will be as follows.

Code:

nas1:/abc/test/test1                /test
nas1:/abc/test/test1/test2       /test/abc

You could use awk for same too.

Code:

awk -vVAL="nas1:/abc/test/test1" '($1==VAL)'  Input_file

Where variable's value is stored in above code as named VAL and it is looking for first field to match it, in case you need to change the string and change the matching field you could change above VAL=new_string_value and in place of $1you could use $2second field or $3 3rd field etc.

Thanks,
R. Singh

Thanks , its working when running directly from terminal.

But when i am passing variable its not working.
I am using this under remote server

Code:

PR="\$( cat filename | awk -vVAL="$my_var" "($1==VAL)")"

Its giving syntax error , any suggestions.

Giving which syntax error? I'll try and guess.

You shouldn't need to put $( ) in quotes, and shouldn't escape the dollar sign.

Also, that's a useless use of cat. awk ... filename ought to do the same thing without the cat.

Actually i am running this command remotely under the script , so it won;t run without escape the dollar sign

I have to grep this from df command , so i am using like below

Code:

PR="\$(df -hTP | awk -vVAL="$my_var" ($1==VAL))"

/bin/bash: command substitution: line 11: syntax error near unexpected token `('

Moderator's Comments:

Please use code tags even for so little, thanks

Code:

PR="$(df -hTP | awk -vVAL="$my_var" '$1==VAL')"

What exactly is not working? How do the grep versions differ on the various system? How the input files (<TAB> / space separated?)?
Please note the -w wouldn't succeed, as / is NOT a word constituent character.