BASH as a Command Line Interface

It is nontrivial, but the first thing you should try is:

stty ^?

If that does not work, read the following links for more details

• Fix delete & backspace in tmux
• Keyboard-and-Console-HOWTO: Delete and Backspace
• Linux Backspace/Delete mini-HOWTO

By default, the flow control is enabled. That is, if C-s is pressed, the output will "freeze". Note that the terminal is still accepting inputs, it is just the output that is paused. A C-q will restart the output.

Nowadays, we are using terminal emulators most of the time and this feature only services to obfuscate and confuse. Hence, turn it off with the following command:

stty -ixon

Use C-q or C-v to escape the characters. For example, to enter ^M, i.e. '\r' (CR: Carriage Return, ascii 0x0d):

1. Press C-q (or C-v if C-q is interpreted as XOFF)
2. Then, press C-m

• To list available key-bindings

  bind -p
  

• Refer to inputrc section in my profile

• type [-a] cmd
• help cmd (for shell builtin, like man for non-builtins)
• which cmd
• whereis cmd

$ type printf
printf is a shell builtin

$ type -a printf
printf is a shell builtin
printf is /usr/bin/printf

$ help printf
printf: printf [-v var] format [arguments]
     printf formats and prints ARGUMENTS under control of the FORMAT. FORMAT
     ...

$ which printf
/usr/bin/printf

$ whereis printf
printf: /usr/bin/printf /usr/include/printf.h ...

Prepend the command with a backslash. Say, your ls is an alias to ls --color=auto, and now you want the original ls. just \ls.

NOTE that, in bash, aliases are disabled automatically in non-interactive sessions (scripts).

• autocd
• cdspell
• dirspell

For bash, check (info "(bash) Directory Stack Builtins") for usage of pushd, popd, dirs. Refer to my profile for a simple wrapper which makes it even more convenient.

Also, take a look at the lsdm, dN, gN (and dumpdm, loaddm) in my profile. This solution is complementary to pushd. It facilitates bookmarking directories.

dN

bookmark current directory as gN

gN

goto corresponding bookmarked directory

lsdm

list current directory bookmark

Here is an example of how to use it:

• Remember directories and jump to them easily

  [994] 10:05:46 lungangfang@qdbuild2 ~
  $ cd sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86/
  
  [995] 10:05:59 lungangfang@qdbuild2 ~/sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86
  $ d0
  
  [1000] 10:06:02 lungangfang@qdbuild2 ~/sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86
  $ lsdm
  g0='cd /home/lungangfang/sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86'
  
  [1001] 10:06:05 lungangfang@qdbuild2 ~/sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86
  $ cd ~/tmp
  
  [1002] 10:06:11 lungangfang@qdbuild2 ~/tmp
  $ d1
  
  [1003] 10:06:51 lungangfang@qdbuild2 ~/tmp
  $ cd ~/doc/sdm
  
  [1004] 10:06:59 lungangfang@qdbuild2 ~/doc/sdm
  $ d2
  
  [1005] 10:07:03 lungangfang@qdbuild2 ~/doc/sdm
  $ lsdm
  g0='cd /home/lungangfang/sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86'
  g1='cd /home/lungangfang/tmp'
  g2='cd /home/lungangfang/doc/sdm'
  
  [1006] 10:07:05 lungangfang@qdbuild2 ~/doc/sdm
  $ g0
  
  [1007] 10:07:08 lungangfang@qdbuild2 ~/sandbox/main/TelicaRoot/components/sp_system/scripts_rhx86
  $ g1
  
  [1008] 10:07:11 lungangfang@qdbuild2 ~/tmp
  $ g2
  
  [1009] 10:07:13 lungangfang@qdbuild2 ~/doc/sdm
  

• Persist and load directory marks between sessions

  [1030] 10:09:24 lungangfang@qdbuild2 ~/sandbox/fid16665
  $ cat ~/.dir_mark
  alias g0='cd /home/lungangfang/sandbox/aluac'
  alias g1='cd /home/lungangfang/sandbox/BRANCH-8-3-0-5'
  alias g2='cd /home/lungangfang/sandbox/fid16665'
  
  
  [1031] 10:09:11 lungangfang@qdbuild2 ~/sandbox/fid16665
  $ loaddm
  
  [1030] 10:09:22 lungangfang@qdbuild2 ~/sandbox/fid16665
  $ lsdm
  g0='cd /home/lungangfang/sandbox/aluac'
  g1='cd /home/lungangfang/sandbox/BRANCH-8-3-0-5'
  g2='cd /home/lungangfang/sandbox/fid16665'
  
  [1032] 10:13:11 lungangfang@qdbuild2 ~/sandbox/fid16665
  $ d0
  
  [1033] 10:14:28 lungangfang@qdbuild2 ~/sandbox/fid16665
  $ dumpdm
  
  [1034] 10:14:38 lungangfang@qdbuild2 ~/sandbox/fid16665
  $ cat ~/.dir_mark
  alias g0='cd /home/lungangfang/sandbox/fid16665'
  alias g1='cd /home/lungangfang/sandbox/BRANCH-8-3-0-5'
  alias g2='cd /home/lungangfang/sandbox/fid16665'
  

  If you are using bash, maybe you can put "dumpdm" to .bash_logout to automatically dump directory marks. and put "loaddm" into .bash_profile (or .bashrc) to load directory marks automatically.

Say, you are in "/home/lgfang/1.0/demo/test" and you want to change directory to "/home/lgfang/2.0/demo/test".

In ksh, you can just cd 1.0 2.0, but Bash does not provide this. Here is small function to simulate that.

function cdr {
    # cdr from to
    if [ $# -ne 2 ]; then
        echo "Usage: cdr from to" >&2
        return 1
    fi

    cd "${PWD/$1/$2}"
}

In addition to C-r (suppose you have not set -o vi) to search backward in command history, this section gives some examples for other frequently used features.

For more detailed and more accurate info, refer to (info "(bash)Using History Interactively").

• Before try the techniques described below, you might want to add this to profile so that you get a chance to look at the resulted command instead of running it directly.

  shopt -s histverify
  

• !N:xxx to retrieve the N^th command and tweak it.

  Suppose the 1025^th command is this:

  $ to -a -s bono08
  

  Then:

  | input                | result          | comment                  |
  |----------------------+-----------------+--------------------------|
  | !1025                | to -a -s bono08 | the whole command        |
  | !1025:*              | -a -s bono08    | all parameters           |
  | !1025:^              | -a              | first parameter          |
  | !1025:$              | bono08          | last parameter           |
  | !1025:2-3            | -s bono08       | 2nd-3rd parameters       |
  | !1025:s/bono08/hp25/ | to -a -s hp25   | replace bono08 with hp25 |
  

• !str:xxx works the same way except it designates the last command which starts with string "str".
• !#:xxx for current command line typed so far
• !!:xxx for the last command
• !-N:xxx for command N lines back (!-1 == !!).
• To print history number in PS1

  export PS1='[\!]\$ '
  

• Refer to my profile for the usage of history-search-backward.

Refer to my profile

Refer to my profile

Usually, we do not write scripts of programmable completion by ourselves. We just google and download ready-made scripts.

To "install" those scripts,

• Simply put them file into a standard completion directory such as /etc/bash_completion.d/. Or,
• Put them to anywhere you see as appropriate and source it in your bashrc.

  if [ -d $HOME/.bash_completion.d ]; then
      for each in $HOME/.bash_completion.d/*; do
          source $each
      done
  fi
  

To write your own auto-completion, it is really easy to get started. Here is an example:

complete -W "list of all words for an automatic completion" your_command

Refer to following resources for more details http://www.gnu.org/software/bash/manual/html_node/Programmable-Completion-Builtins.html#Programmable-Completion-Builtins http://www.debian-administration.org/article/316/An_introduction_to_bash_completion_part_1 http://www.debian-administration.org/article/316/An_introduction_to_bash_completion_part_2

• One way to change them as indicated by /etc/profile.d/colorls.sh is to create your own version of .dir_colors.$TERM.

  COLORS=/etc/DIR_COLORS
  [ -e "/etc/DIR_COLORS.$TERM" ] && COLORS="/etc/DIR_COLORS.$TERM"
  [ -e "$HOME/.dircolors" ] && COLORS="$HOME/.dircolors"
  [ -e "$HOME/.dir_colors" ] && COLORS="$HOME/.dir_colors"
  [ -e "$HOME/.dircolors.$TERM" ] && COLORS="$HOME/.dircolors.$TERM"
  [ -e "$HOME/.dir_colors.$TERM" ] && COLORS="$HOME/.dir_colors.$TERM"
  # ...
  eval `dircolors --sh "$COLORS" 2>/dev/null`
  

• An simpler way is, if you only change one color or two, is to put the following line into your .bashrc:

  export LS_COLORS='di=38;5;33'
  # NOTE: this will wipe out other LS_COLORS settings
  

• Format:

  \[\e[color_code+m\]
  

• Example:

  # for 256-color
  PS1='\n\[\e[38;5;10m\][\!] \t \[\e[38;5;106m\]\u@\h'
  PS1=$PS1' \[\e[38;5;33m\]\w\n\[\e[32m\]\$\[\e[0m\] '
  
  # a similar one for 8-color
  PS1='\n\[\e[32m\][\!] \t \[\e[33m\]\u@\h'
  PS1=$PS1' \[\e[34m\]\w\[\e[32m\]\n\$\[\e[0m\] '
  

http://misc.flogisoft.com/bash/tip_colors_and_formatting

Also refer to /etc/DIR_COLORS or /etc/DIR_COLORS.256color for detailed explaination of codes for colors. Even though it is for ls, the codes also applicable to PS1.

for i in {0..255};do echo -e "\x1b[38;5;${i}mcolour${i}"; done

or

for i in {0..255};do printf "\x1b[48;5;${i}m ";done;printf "\x1b[0m\n"

or

#!/bin/bash
for i in {0,1,29,30,31};do
    printf "$((i*8))\t"
    for j in {0..7}; do
        printf "\x1b[48;5;$((i*8+j))m  "
    done
    printf "\x1b[0m\n"
done
for red in {0..5}; do
    printf "$((16+red*36))\t"
    for green in {0..5};do
        for blue in {0..5}; do
            printf "\x1b[48;5;$((16+red*36+green*6+blue))m  "
        done
        printf "\x1b[0m "
    done
    printf "\x1b[0m\n"
done