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FAST Search and Replace for Strings in all Files in Directory
I needed a way to search all files in a web directory that contained a certain string, and replace that string with another string. In the example, I am searching for "askapache" and replacing that string with "htaccess". I wanted this to happen as a cron job, and it was important that this happened as fast as possible while at the same time not hogging the CPU since the machine is a server. So this script uses the nice command to run the sh shell with the command, which makes the whole thing run with priority 19, meaning it won't hog CPU processing. And the -P5 option to the xargs command means it will run 5 separate grep and sed processes simultaneously, so this is much much faster than running a single grep or sed. You may want to do -P0 which is unlimited if you aren't worried about too many processes or if you don't have to deal with process killers in the bg. Also, the -m1 command to grep means stop grepping this file for matches after the first match, which also saves time.

get a fresh commandlinefu-item each day as motd
Commandline-fu often has little tricks that I always forget. By adding this to the root-cron (sudo crontab -e) I lean a new trick every day.

Move all files between to date
In a folder with many files and folders, you want to move all files where the date is >= the file olderFilesNameToMove and

back ssh from firewalled hosts
host B (you) redirects a modem port (62220) to his local ssh. host A is a remote machine (the ones that issues the ssh cmd). once connected port 5497 is in listening mode on host B. host B just do a ssh 127.0.0.1 -p 5497 -l user and reaches the remote host'ssh. This can be used also for vnc and so on.

Adding Prefix to File name
Good old bracket expansion :-) For large numbers of files, "rename" will spare you the for-loop, or the find/exec...

Remove text from file1 which is in file2 and stores it in an other file
This command compares file2 with file1 and removes the lines that are in file1 from file2. Handy if you have a file where file1 was the origional and you want to remove the origional data from your file2.

list files recursively by size

Extract dd-image from VirtualBox VDI container and mount it
Tested with NTFS and found on this site: http://forensicir.blogspot.com/2008/01/virtualbox-and-forensics-tools.html The first 32256 bytes is the MBR

put all lines in comment where de word DEBUG is found

Truncate long strings in columns and use custom header names
Using the --table-truncate ( -T ) option, you can specify the columns you will allow to be truncated. This helps when you have some columns that are unusually long, or a small terminal window. In this example we will print out the /etc/passwd file in columns. We are using a colon as our separator ( -s: ), defining that we want table output ( -t ), defining the column names ( -N ) and allowing the column NAME to be truncated ( -T ).


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