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crasic
Asked: 2010-11-10 13:54:57 +0800 CST

iPython Like Command History For Shell

  • 772

For those of you who don't do python programming on ubuntu, ipython is a python shell on steroids, but it has this amazing feature that it not only autcompletes based on known names (i.e. the same way bash does when you press tab), but if you start typing a command and press up, it doesn't scroll through the entire history (like bash) but only through the recent commands that started with the same string of leters.

So if you did some long command like scp -r -P 8000 -l user server.com:~/dir/to/copy ./ followed by several other commands. If you started typing scp and pressed up, bash would display the command shown before instead of just scrolling through the entire history.

Is there an extension like this for bash? or is there any shell that offers this kind of feature?

command-line bash

4 Answers

  1. Best Answer

    Bash does have that feature too, but it's not enabled by default. You can bind it to cursor up/down by sticking this into ~/.inputrc:

    "\e[A": history-search-backward
"\e[B": history-search-forward

    I prefer to bind it to Ctrl+up/down instead:

    "\e[1;5A": history-search-backward
"\e[1;5B": history-search-forward

    edit: To preserve ctrl+left and ctrl+right for moving back and forward in whole words, also include these lines in ~/.inputrc file:

    # mappings for Ctrl-left-arrow and Ctrl-right-arrow for word moving
"\e[1;5C": forward-word
"\e[1;5D": backward-word
"\e[5C": forward-word
"\e[5D": backward-word
"\e\e[C": forward-word
"\e\e[D": backward-word
    • 31

  2. Try hitting Ctrl + R, and typing a few letters. It works in the reverse order as well.

    • 9

  3. And don't forget the fantastic history expansion shortcuts in bash. 1

    I'm posting some excerpts from the manpage, in case you haven't tattooed them on your arm (or memorized them). 

       Event Designators  
       An event designator is a reference to a command line entry in the  his‐
       tory list.

       !      Start  a  history substitution, except when followed by a blank,
              newline, carriage return, = or ( (when the extglob shell  option
              is enabled using the shopt builtin).
       !n     Refer to command line n.
       !-n    Refer to the current command line minus n.
       !!     Refer to the previous command.  This is a synonym for `!-1'.
       !string
              Refer to the most recent command starting with string.
       !?string[?]
              Refer  to the most recent command containing string.  The trail‐
              ing ? may be omitted if string is followed immediately by a new‐
              line.
       ^string1^string2^
              Quick  substitution.  Repeat the last command, replacing string1
              with string2.  Equivalent to ``!!:s/string1/string2/'' (see Mod‐
              ifiers below).
       !#     The entire command line typed so far.

    I frequently use the ability to refer to the last 'word' of the previous command. E.g., 

    mkdir /foo/shmoo/adir.horribilus.foo
cp file1 file2 file3 file4 !$ 
ls -l !$

    In both cases here, the !$ matches /foo/shmoo/adir.horribilus.foo .

    1... which were taken from csh. To mitigate the scope of bash's feature theft, the bash man page says 

       The shell supports a history expansion feature that is similar  to  the
   history  expansion in csh.

    So, it's "similar". Any of this might break in csh or tcsh. Or whichever csh descendent you are not using due to the fact that it isn't as wonderful as bash .

    • 6

  4. There is an alternative similar to what @ak2 mentioned above, but you do not have to create a new .inputrc file.

    Instead, if you have sudo permissions, you can enable this in the /etc/inputrc file. In this file are various keyboard settings including the history search feature (for 18.04 at least). The excerpt from /etc/inputrc is:

    # alternate mappings for "page up" and "page down" to search the history
# "\e[5~": history-search-backward
# "\e[6~": history-search-forward

    Simply uncomment the bottom two lines using a sudo file editor (e.g., $ sudo vim), and a new terminal session will have the history search feature (for all users).

    • 1