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Some shell newbies don't know this very handy file management related command so I decided to include it here.
You need to have the "file" package installed.
Rename all mp4 files with crc32 information.
Videos are found using their MIME type. Thus no need to for an extension for the video file.
This is a efficent version of "jnash" cmd (4086). Thanks for jnash. This cmd will only show video files while his cmd show files having "video" anywhere in path.
If you make a mess (like I did) and you removed all the executable permissions of a directory (or you set executable permissions to everything) this can help.
It supports spaces and other special characters in the file paths, but it will work only in bash, GNU find and GNU egrep.
You can complement it with these two commands:
1. add executable permission to directories:
find . type d -print0 | xargs -0 chmod +x
2. and remove to files:
find . type d -print0 | xargs -0 chmod -x
Or, in the same loop:
while IFS= read -r -u3 -d $'\0' file; do
case $(file "$file" | cut -f 2- -d :) in
chmod +x "$file"
chmod -x "$file"
esac || break
done 3< <(find . -print0)
Ideas stolen from Greg's wiki: http://mywiki.wooledge.org/BashFAQ/020
Using gentoo prefix portage I got in a situation where some packages did not contain the needed RPATH variable. This command helped me to find out which ones I should recompile
does the -i option open a tmp file?
this method does not.
If you used to do `vlc /tmp/Flash*`, but no longer can't, this is for you.
This is a better version, as it does no command piping, uses for instead of while loops, which allows for a list of files in the current working directory to be natively processed. It also uses the -v/verbose option with mv to let you know what the command is doing.
While the command does exactly the same in a better way, I would modify the sed option to replace spaces with underscores instead, or dashes.
Please note that you'll receive errors with this command as it tries to rename files that don't even have spaces.
file(1) can print details about certain devices in the /dev/ directory (block devices in this example). This helped me to know at a glance the location and revision of my bootloader, UUIDs, filesystem status, which partitions were primaries / logicals, etc.. without running several commands.
file -s /dev/dm-*
file -s /dev/cciss/*
This command deletes the "newline" chars, so its output maybe unusable :)
It's works only when you replace '\n' to ONE character.
Should be a bit more portable since echo -e/n and date's -Ins are not.
This is useful when watching a log file that does not contain timestamps itself.
If the file already has content when starting the command, the first lines will have the "wrong" timestamp when the command was started and not when the lines were originally written.
So your boss wants to know how much memory has been assigned to each virtual machine running on your server... here's how to nab that information from the command line while logged in to that server