Ubuntu – How should I glob for all hidden files

bashcommand linefileswildcards

I want to carry out some action (say chown) on all the hidden files in a directory.

I know that this .* is not a good idea because it will also find the current . and parent .. directories (I know that rm will fail to operate on . and .. but other commands, including chown and chmod, will happily take effect)

But all my hidden files have different names!

How should I glob for all hidden files while excluding . and .. ?

Best Answer

You can use the following extglob pattern:

.@(!(.|))

. matches a literal . at first
@() is a extglob pattern, will match one of the patterns inside, as we have only one pattern inside it, it will pick that
!(.|) is another extglob pattern (nested), which matches any file with no or one .; As we have matched . at start already, this whole pattern will match all files starting with . except . and ...

extglob is enabled on interactive sessions of bash by default in Ubuntu. If not, enable it first:

shopt -s extglob

Example:

$ echo .@(!(.|))
.bar .foo .spam

Related Solutions

Ubuntu – How to periodically turn off showing hidden files

You can use gsettings to access the responsible setting in the dconf registry easily from the command line.

The setting whether to show hidden files (with names starting with .) is located in the schema org.gtk.Settings.FileChooser and called show-hidden.

Allowed values are either true (show hidden files) or false (don't show them).

So here are the commands to enable or disable showing the hidden files:

gsettings set org.gtk.Settings.FileChooser show-hidden true
gsettings set org.gtk.Settings.FileChooser show-hidden false

To automatically run this command every x minutes, there are two good resources to learn how to achieve this:

Using cron (minimum resolution is 1 minute): help.ubuntu.com: Cron How-to

Note that cron runs tasks with a very limited set of env variables which do not include DBUS_SESSION_BUS_ADDRESS, but that's needed for gsettings to work. So we have to take care of setting this variable ourselves in the script we run if we need it

I prepared a script for you (with the help of @JacobVlijm who linked me this answer on Stack Overflow by @Radu Rădeanu) that takes care of this problem and can be run directly by cron:
```
#!/bin/bash

# --> Script to disable showing hidden files - to be run as cron job <--

# export DBUS_SESSION_BUS_ADDRESS environment variable
PID=$(pgrep gnome-session)
export DBUS_SESSION_BUS_ADDRESS=$(grep -z DBUS_SESSION_BUS_ADDRESS /proc/$PID/environ|cut -d= -f2-)

gsettings set org.gtk.Settings.FileChooser show-hidden false
```
Without using cron: How to execute command every 10 seconds (without cron)?

Ubuntu – What does ls -al .* command return

ls -al .* shows the contents of all directories in the current directory whose names begin with . (ie all those matching the shell glob .*)

In Bash, the .* glob resolves to . and .. as well. Since . represents the current directory, and .. the parent directory, the contents of both of these directories, including any hidden files and directories, are shown too.¹

.* also catches hidden files in the current directory, but they are listed anyway as contents of .

As explained in What does `ls --directory` stand for? the -d flag causes the directories themselves to be displayed, instead of their contents.

¹_{this is also the case in dash, which is the shell symlinked to sh in Ubuntu. However, other shells, including zsh and mksh, behave more intuitively and don't include . and .. when expanding .*. It is also worth noting that, while most commands will operate on .. and . when they are included in a .* glob (including chmod and chown - you can really mess up your system with those), the rm command will helpfully fail by design to do so.}

Best Answer

Related Solutions

Ubuntu – How to periodically turn off showing hidden files

Ubuntu – What does ls -al .* command return

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