Unix/Bash: Redirect results of find command so files are used as input for other command - linux

I've got a directory structure that contains many different files named foo.sql. I want to be able to cd into this directory & issue a command like the following:
find . -name "foo.sql" -exec mysql -uUserName -pUserPasswd < {} \;
where {} is the relative path to each foo.sql file. Basically, I want:
mysql -uUserName -pUserPasswd < path/to/foo.sql
to be run once for each foo.sql file under my subdirectory. I've tried Google & it's been not much help. Ideally this would be part of a UNIX shell script.
Thanks in advance, & sorry if it's been asked before.

The -exec option doesn't run a shell, so it can't process shell operators like redirection. Try this:
find . -name "foo.sql" -exec cat {} + | mysql -uUserName -pUserPasswd
cat {} will write the contents of all the files to the pipe, which will then be read by mysql.

Or, just to point out another approach:
find . | xargs cat | mysql etcetera
xargs is a generic pipe operation roughly equivalent to find's '-exec'. It has some advantages, some disadvantages, depending on what you're doing. Intend to use it because i'm often filtering the list of found files in an earlier pipeline stage before operating on them.
There are also other ways of assembling such command lines. One nice thing about Unix's generic toolkits is that there are usually multiple solutions, each with its own tradeoffs.

Related

Simple Bash Script that recursively searches in subdirs for a certain string

i recently started learning linux because a ctf contest is coming in the next months. The problem that I struggle with is that i am trying to make a bash script that starts from a directory, checks if the content is a directory or other kind of file. If it is a file,image etc apply strings $f | grep -i 'abcdef', if it is a directory cd to that directory and start over. i have c++ experience and i understand the logic but i can't really make it work.I can't succesfully implement the loop that goes thru all the subdirectories. All help would be appreciated!
you don not need a loop for this implementation. The find command can do what you are looking after.
for instance:
find /home -type f -exec sh -c " strings {} | grep abcd " \;
explain:
/home is you base directory can be anything
-type f: means a regular file
-exec from the man page:
"Execute command; true if 0 status is returned. All
following arguments to find are taken to be arguments to
the command until an argument consisting of ;' is encountered. The string {}' is replaced by the current
file name being processed everywhere it occurs in the
arguments to the command, not just in arguments where it
is alone, as in some versions of find. Both of these
constructions might need to be escaped (with a `') or
quoted to protect them from expansion by the shell. See
the EXAMPLES section for examples of the use of the -exec
option. The specified command is run once for each
matched file. The command is executed in the starting
directory. There are unavoidable security problems
surrounding use of the -exec action; you should use the
-execdir option instead."
If you want to just find the string in a file and you do not HAVE TO first find a directory and then a file and then search, you can just simply find the text with grep.
Go to the the parent directory and execute :
grep -iR "abcd"
Or from any place,
grep -iR "abcd" /var/log/mylogs/
Suggesting a grep command on find filter results:
grep "abcd" $(find . -type f)

Shell Script to finding files in specific folder and based on "age" of files

hello i got homework to make a shell script in linux to find a file in specific folder based on the "age" of those files. and after that i want to move that file to other specific folder.
thank you before
One way is to use the find command, and specify the "age" with -mtime (or -newer if age relative to other files). See man find for more details.
To move the files you can use mv (again, see man mv).
Directories can be passed as arguments or stored in variables and then used
as variables in the commands.
Without knowing anything else about your assignment I'd say use something like this:
find <directory> -mtime <n> | xargs mv -t <destination>
where xargs is used to pass the results from find to the mv command.

Find in Linux combined with a search to return a particular line

I'm trying to return a particular line from files found from this search:
find . -name "database.php"
Each of these files contains a database name, next to a php variable like $dname=
I've been trying to use -exec to execute a grep search on this file with no success
-exec "grep {\}\ dbname"
Can anyone provide me with some understanding of how to accomplish this task?
I'm running CentOS 5, and there are about 100 database.php files stored in subdirectories on my server.
Thanks
Jason
You have the arguments to grep inverted, and you need them as separate arguments:
find . -name "database.php" -exec grep '$dbname' /dev/null {} +
The presence of /dev/null ensures that the file name(s) that match are listed as well as the lines that match.
I think this will do it. Not sure if you need to make any adjustments for CentOS.
find . -name "database.php" -exec grep dbname {} \;
I worked it out using xargs
find . -name "database.php" -print | xargs grep \'database\'\=\> > list_of_databases
Feel free to post a better way if you find one (or what some rep for a good answer)
I tend to habitually avoid find because I've never learned how to use it properly, so the way I'd accomplish your task would be:
grep dbname **/database.php
Edit: This command won't be viable in all cases because it can potentially generate a very long argument list, whereas find executes its command on found files one by one like xargs. And, as I noted in my comment, it's possibly not very portable. But it's damn short ;)

Shell Piping the data in middle of another command

If I need to have scripts like below:
find -name 'lib*.so' | xargs cp <files> ~/libs/.
Where < files > is the file which I found from the previous find command. Basically i want to pipe the data not just at the end but some where in the middle. (Some thing like $1 ???)
I understand I can have small sh file, where I can have this in a variable and use For loop & use that variable.... But what I want is simple one as I explained above. Where simple tasks can be accomplished easily.
Note: The script above is only a indication of type of Problem and the actual problem.
Let me know if this kind is possible.
If you just want to do copy
find -name 'lib*.so ' -print0 | xargs -r0 cp --target ~/libs/
You can do this using find only, without having to spawn cp(1) for each file by doing:
find -name 'lib*.so' -exec cp -t ~/libs {} +
Note that this only works with GNU cp and a POSIX 2008 compliant find, like GNU find.
I hope I understand what you're trying to do here...
You can do this using find only.
find -name 'lib*.so' -exec cp {} ~/libs/ \;

How do I write a bash script to replace words in files and then rename files?

I have a folder structure, as shown below:
I need to create a bash script that does 4 things:
It searches all the files in the generic directory and finds the string 'generic' and makes it into 'something'
As above, but changes "GENERIC" to "SOMETHING"
As above, but changes "Generic" to "Something"
Renames any filename that has "generic" in it with "something"
Right now I am doing this process manually by using the search and replace in net beans. I dont know much about bash scripting, but i'm sure this can be done. I'm thinking of something that I would run and it would take "Something" as the input.
Where would I start? what functions should I use? overall guidance would be great. thanks.
I am using Ubuntu 10.5 desktop edition.
Editing
The substitution part is a sed script - call it mapname:
sed -i.bak \
-e 's/generic/something/g' \
-e 's/GENERIC/SOMETHING/g' \
-e 's/Generic/Something/g "$#"
Note that this will change words in comments and strings too, and it will change 'generic' as part of a word rather than just the whole word. If you want just the word, then you use end-word markers around the terms: 's/\<generic\>/something/g'. The -i.bak creates backups.
You apply that with:
find . -type f -exec mapname {} +
That creates a command with a list of files and executes it. Clearly, you can, if you prefer, avoid the intermediate mapname shell/sed script (by writing the sed script in place of the word mapname in the find command). Personally, I prefer to debug things separately.
Renaming
The renaming of the files is best done with the rename command - of which there are two variants, so you'll need to read your manual. Use one of these two:
find . -name '*generic*' -depth -exec rename generic something {} +
find . -name '*generic*' -depth -exec rename s/generic/something/g {} +
(Thanks to Stephen P for pointing out that I was using a more powerful Perl-based variant of rename with full Perl regexp capacity, and to Zack and Jefromi for pointing out that the Perl one is found in the real world* too.)
Notes:
This renames directories.
It is probably worth keeping the -depth in there so that the contents of the directories are renamed before the directories; you could otherwise get messages because you rename the directory and then can't locate the files in it (because find gave you the old name to work with).
The more basic rename will move ./generic/do_generic.java to ./something/do_generic.java only. You'd need to run the command more than once to get every component of every file name changed.
* The version of rename that I use is adapted from code in the 1st Edition of the Camel book.
Steps 1-3 can be done like this:
find .../path/to/generic -type f -print0 |
xargs -0 perl -pi~ -e \
's/\bgeneric\b/something/g;
s/\bGENERIC\b/SOMETHING/g;
s/\bGeneric\b/Something/g;'
I don't understand exactly what you want to happen in step 4 so I can't help with that part.

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