DirB, Directory Bookmarks for Bash

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Inspired by browser bookmarks, DirB allows you to create directory bookmarks for moving around faster on the command line.
Listing the Saved Bookmarks

DirB's sl command prints a saved bookmark listing. It has two forms. The simplest form lists the files across the line, from left to right, in reverse time order, most recently accessed bookmark first:

% sl
d test prod tmp beta alpha

In this example, the bookmark for my desktop, d, was accessed most recently.

In the longer form, sl lists the date and time that each bookmark was last referenced:

% sl -l
2010-03-10 14:42 d
2010-03-01 14:19 test
2010-02-27 10:17 prod
2010-02-27 14:21 tmp
2009-10-22 17:26 beta
2009-08-05 11:37 alpha

In this fuller listing, you can see that the d bookmark was referenced on March 10th, and the last time that the test bookmark was referenced was nine days earlier. If the long listing does not fit on a screen, the less command will page through the listing automatically.

It is possible to pass a regular expression to sl and list only the matching bookmarks. To list the saved bookmarks that begin with the letter t:

% sl "t*"
test  tmp
% sl -l "t*"
2010-03-10 14:19 test
2010-02-27 14:21 tmp

Note that the regular expression needs to be protected by double (or single) quotes to prevent the shell from trying to expand it before it is seen by the sl command.

Whenever a bookmark is the target of a g, p or s command, its timestamp is updated to record the reference. However, timestamps are not updated when a directory is accessed using cd, pushd or by directory stack manipulations.

Removing Stale Bookmarks

Directory bookmarks are so easy to make that I create them frequently. Many of my bookmarks are short-lived. If left unchecked, the saved bookmark listing would become very long and cluttered. DirB's r command simplifies the removal of unwanted bookmarks:

% sl
test  prod  d  tmp  beta  alpha
% r alpha
% sl
test  prod  d  tmp  beta

The second saved bookmark listing shows that the r alpha removed the unwanted alpha bookmark.

DirB or the underlying Bash commands issue error messages when a problem is encountered. Accessing a deleted bookmark results in such a message:

% g alpha
bash: cd: alpha: No such file or directory

This is the error message issued when a bookmark does not exist, possibly due to a misspelling.

Using Bookmarks in Scripts

Bookmarks save keystrokes and allow for fast movement between directories. Bookmarks also can be used to make scripts more portable. By referencing bookmarks, instead of fixed paths, it is possible to re-use scripts in different environments easily. I work on both Linux and Cygwin platforms. (Cygwin is a Linux-like environment for Windows platforms. For more information, or to download Cygwin, see www.cygwin.com.) Because Cygwin presents a very Linux-like look and feel, the transitions are painless. However, the Linux and Cygwin directory structures are different. I use DirB to set up the same list of common bookmarks on each system. This way, I can change between directories on the command line with the same keystrokes, regardless of the platform.

In addition to Linux and Cygwin environments, DirB has been tested on BSD UNIX and Mac OS X platforms. So, the flexibility of DirB bookmark references can span across a variety of systems.

The d command extends the DirB facility to shell scripts. (The d is short for either “display bookmark path” or “dereference bookmark path”, your choice.) It allows a script to obtain the full pathname of a bookmark's directory.

Bash's command substitution $(command) feature usually is used to access d:

% DTOP="$(d d)"
% echo $DTOP
/home/Desktop

The double quotes need to surround the shell substitution in case there are spaces in the directory path. Unfortunately, this is all too common on the Windows-based Cygwin platform, so I always use the quotes. In the above example, the shell variable $DTOP could be used to access the desktop. To create a new log file on the desktop, the output of a command could be redirected to $DTOP/logfile. Do not forget the double quotes, in case the dereferenced path includes spaces.

I recommend the use of Bash's substitution feature, as shown above. However, a shorter way to print out the name of the path is to use DirB's d command directly:

% d d
/home/Desktop

______________________

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you can just add in your

Anonymous's picture

you can just add in your .bash_profile

export hello=~/tmp/hello
source .bash_profile
cd $hello

you can still use the tab to autocomplete

done

you can just add in your

Keith Daniels's picture

Thanks...

I knew I could export directories like that but it never dawned on me that autocomplete would still work.... duh. One track mind....

When I tested this, I could not get autocomplete to work with cd. It would work with ls or any other program except cd. Dont' know why, probably some bashrc or profile setting I used is blocking it.

----

BTW I just noticed something about using cd in Ubuntu Maverick that I "think" is a new (or just something I never noticed ) feature:

If you have a sub-directory called ~/test/test and when using cd you mistakenly type:

cd ~/text/text

It will take you to ~/test/test -- instead of giving you an error message -- if that is the only directory with similar spelling on you computer.

Personally I think that is wonderful...

Keith

"I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone."
-- Bjarne Stroustrup

Yes...! Something I never could figure out how to do...

Keith Daniels's picture

Something I always wanted and never could figure out how to do...

Good Idea!
Great Post!
Excellent Explanation!

Thanks.

"I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone."
-- Bjarne Stroustrup

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