Commands using ls

This will show all physically connected SATA (and SCSI) drives on your system. This is particularly useful when troubleshooting hard disks.... or when a mount point seems to be missing.

Find files that are older than x days in the working directory and list them. This will recurse all the sub-directories inside the working directory.

By changing the value for -mtime, you can adjust the time and by replacing the ls command with, say, rm, you can remove those files if you wish to.

Note that the file at the given path will have the contents of the (still) deleted file, but it is a new file with a new node number; in other words, this restores the data, but it does not actually "undelete" the old file.

I posted a function declaration encapsulating this functionality to http://www.reddit.com/r/programming/comments/7yx6f/how_to_undelete_any_open_deleted_file_in_linux/c07sqwe (please excuse the crap formatting).

Many sites with Flash video players will download video files to /tmp on Linux, with temporary filenames like "FlashbGTHm4". These will often play in mplayer, totem, or other movie playing software. You must first navigate to a video page, let it start loading, and then pause playback.

List only hidden files (or directories). You also can use:

This command would be useful when it is desirable to list only the directories.

Other options

Hidden directory

Other path

Long format:

Show you the list of files of current directory sorted by date youngest to oldest, remove the 'r' if you want it in the otherway.

This command specifies the size in Kilobytes using 'k' in the -size +(N)k option. The plus sign says greater than. -exec [cmd] {} \; invokes ls -l command on each file and awk strips off the values of the 5th (size) and the 9th (filename) column from the ls -l output to display. Sort is done in reversed order (descending) numerically using sort -rn options.

A cron job could be run to execute a script like this and alert the users if a dir has files exceeding certain size, and provide file details as well.

cat file1 file2 file3|sort|uniq -d

finds the same lines in several files, especially in files with lists of files.

Get simple description on each file from /bin dir, in list form, usefull for newbies.

Very useful for finding all files over a specified size, such as out of control log files chewing up all available disk space. Fedora Core x specific version.

Prints a graphical directory tree from your current directory

Do ls with permissions written in octal form.

Shows the current directory and those below it in a simple tree structure. Recommended use:

alias lt='$command_above'

This command would be useful when it is desirable to list only the directories. 'egrep' chooses only the lines that begin with 'd'.

Useful for examining hostile processes (backdoors,proxies)