[Eug-lug] Strange shell behavior

[Martin Kelly]

Yes, the example below would've worked... I think my problem was missing 
double quotes screwing up the parsing of spaces. I actually don't have a 
reason not to do it the simple way, however; it's just that I don't know 
much about grep/bash. I think I'm going to use grep -lr, as it is giving 
the output I wanted.

Thanks,
Martin

Bob Miller wrote:
> Martin Kelly wrote:
> 
>> I have just written a shell script that greps a directory for a certain 
>> pattern and reports each file that contains the pattern along with the 
>> filename before it (this is why I wrote it... if I just do a "ls | cat | 
>> grep pattern" or something like that it will report the text that 
>> matches but not the filename).
>>
>> I am getting strange behavior in that it works, but sometimes it 
>> randomly reports the contents of my / directory. This does not always 
>> happen, only sometimes.
> 
> Have you already considered and rejected doing it the simple way?
> 
>   $ cat misc/dirgrep
>   #!/bin/sh
>   cd "$1"
>   shift
>   grep "$@" *
>   $ misc/dirgrep code/c/kr/1/ MAXLINE
>   1-16.c:#define MAXLINE 1000 /* maximum input line size */
>   1-16.c:char  line[MAXLINE]; /* current input line */
>   1-16.c:char longest[MAXLINE]; /* longest line  saved here */
>   1-16.c:while ((len = getline(line, MAXLINE)) > 0)
>   1-17.c:#define MAXLINE 1000 char line[MAXLINE]; while ((len = getline(line, MAXLINE)) > 0) {
> 
> Also note that "grep -r ..." will recursively search subdirectories.
> That's useful sometimes.  You could just say
> 
>   $ grep -r MAXLINE code/c/kr/1/
> 
> If you have reason not to do it that way, you can fix your script by
> not using backslashes (it runs the output lines together) and by
> quoting $TEXT in the echo command.
> 
> You don't need to save and restore the current directory.  Each
> shell script runs in its own process, and each processs has its
> own current directory.  So when the script exits, the kernel
> forgets its current directory.
> 
> This would work.
> 
>   #!/bin/bash
>   cd "$1"			# note quotes
>   for file in *
>   do
>     if grep -q "$2" "$file"	# note quotes
>     then
>       echo
>       echo "$file:"
>       echo "-----------------------"
>       grep "$2" "$file"
>     fi
>   done
>