Scripting : useful files commands

Scripting commands can be powerful.

That's why I have decided to write a set of articles dedicated to commands by category.

Today the category is relative to files and folders : the commands below are useful when you need to handle files via the Terminal or when scripting.

Some of them are only available on Haiku, so enjoy :)

command	description
cd	Changes the current working directory
ls	Lists the contents of a directory
pwd	Prints the current working directory
stat	Displays detailed information about a file or directory
du	Estimates file or directory disk usage
filepanel (haiku)	Opens a file selection dialog from the Terminal
open (haiku)	Opens files, applications or directories
findpaths (haiku)	Finds system paths for a given resource, like libraries or settings

Change directory

The "cd" command allows to change the current directory in a Terminal.

If you need to go back to your home, you can type one of the below commands : 

cd ~
cd /boot/home
cd 
cd $HOME

The last command use the environment variable named "HOME".

You can check which variables are available via the "env" command : 

And if you need to go up one directory level, type : 

cd ..

Print working directory 

The "pwd" command shows the full path of the current directory :

pwd

If you look at the possible alternative to display the current directory, you can :

• use the "PWD" environment variable
• display the result of the `pwd` command
• or just use the "pwd" command :)

Please note that "OLDPWD" environment variable provides the latest directory used before the current one.

You can change the directory to "OLDPWD" with the below command : 

cd -

List directory contents

What about listing the content of a directory ?

For that you need to use the "ls" command.

You can for instance list the directory details in reverse order (from the oldest to the most recent) :

ls -lrt 

Now let's display the hidden files : 

ls -la 

The ".htaccess" is an hidden file :)

If you want to discover all the possible options of the "ls" command, you can type :

ls --help 

Display file/directory details

The "stat" command gives detailed information such as size, permissions, and timestamps.

Type this command followed by a file or directory name : 

stat info.php

As you can see, it will give a lot of information of the file.

If you need - for a specific reason - to only retrieve one information, you can use the "format" option as below : 

stat --format="%s" info.php

Only the size of the file is retrieved :)

If you need to have the details of the format, you can have it with the "help" option :

stat --help

Estimate disk usage

If you need to have an estimation of the size of each folder in the "www" directory, type :

du -sh */

Nice isn't it ? 

As for previous commands, you can display the available options :

du --help 

File selection dialog 

Now let's use the Haiku only commands.

Let's start by "filepanel" : 

filepanel -t "Please select a file"

Once the file is selected and validated :

Nice, we have retrieved the filename selected by the user !

You can also select directory only, or disable the multiple files selection.

All the options are available with the help option :

filepanel --help

What about asking for a file and store it in the environment variable named "CHOICE" ?

export CHOICE=`filepanel`
echo $CHOICE

Open file/directory 

Let' use the "open" command !

If you need to open a new Tracker window from the current directory type :

open . 

Great now what about open a new directory in the tracker as requested by the user ?

open `filepanel -k d`

Once the "config" directory has been selected, you will have the below : 

Nice ?

System paths

Let's identify specific system directories or resources up to the findpaths command.

findpaths B_FIND_PATH_LIB_DIRECTORY

What about displaying other kind of paths ?

The possibles values are : 

Kind	Description
B_FIND_PATH_APPS_DIRECTORY	Folder for installed applications
B_FIND_PATH_BIN_DIRECTORY	Directory containing binary executables
B_FIND_PATH_BOOT_DIRECTORY	System boot directory
B_FIND_PATH_CACHE_DIRECTORY	Directory used for system cache
B_FIND_PATH_DATA_DIRECTORY	Folder for application data
B_FIND_PATH_DEVELOP_DIRECTORY	Directory containing development tools and files
B_FIND_PATH_ETC_DIRECTORY	Directory for system configuration files
B_FIND_PATH_FONTS_DIRECTORY	Folder for system fonts
B_FIND_PATH_HEADERS_DIRECTORY	Directory for header files (.h) used in development
B_FIND_PATH_LIB_DIRECTORY	Directory for shared libraries (.so, .a)
B_FIND_PATH_LOG_DIRECTORY	Folder containing system and application logs
B_FIND_PATH_PREFERENCES_DIRECTORY	Directory for user preference files
B_FIND_PATH_SERVERS_DIRECTORY	Folder for system services and daemons
B_FIND_PATH_SETTINGS_DIRECTORY	Folder for application settings
B_FIND_PATH_SYSTEM_DIRECTORY	Directory containing essential system files
B_FIND_PATH_VAR_DIRECTORY	Folder for variable files (logs, temporary states)

It could be interesting in case you need to find all the folders relative to a type of resource :)

Mixing commands

You can of course mix commands together.

Below - for instance - is a way to select a new folder where a new Terminal will be opened :

Terminal -w `filepanel -k d` &

Select the directory of your choice like "Desktop" : 

Tada !

The "Desktop" folder is now opened in a new Terminal : 

How do you use files commands ? 

Let's share your findings in the comments below.