Blog links

Linux Hack, Learn Interesting commands and Play with Linux

Posted by Jassal at Friday, January 13, 2012


 

Trick 1: Perform mkdir and cd using a single command

Sometimes when you create a new directory, you may cd to the new directory immediately to perform some work as shown below.


# mkdir -p /tmp/subdir1/subdir2/subdir3

# cd /tmp/subdir1/subdir2/subdir3

# pwd
/tmp/subdir1/subdir2/subdir3
Wouldn’t it be nice to combine both mkdir and cd in a single command? Add the following to the .bash_profile and re-login.

$ vi .bash_profile

function mkdircd () { mkdir -p "$@" && eval cd "\"\$$#\""; }

Now, perform both mkdir and cd at the same time using a single command as shown below:

# mkdircd /tmp/subdir1/subdir2/subdir3

[Note: This creates the directory and cd to it automatically]

# pwd
/tmp/subdir1/subdir2/subdir3
 
Trick 2: Prompt Command
Bash shell executes the content of the PROMPT_COMMAND just before displaying the PS1 variable.

ramesh@dev-db ~> export PROMPT_COMMAND="date +%H:%M:%S"

22:08:42
ramesh@dev-db ~>

[Note: This displays the PROMPT_COMMAND and PS1 output on different lines]

If you want to display the value of PROMPT_COMMAND in the same line as the PS1, use the echo -n as shown below.
ramesh@dev-db ~> export PROMPT_COMMAND="echo -n [$(date +%H:%M:%S)]"

[22:08:51]ramesh@dev-db ~>

[Note: This displays the PROMPT_COMMAND and PS1 output on the same line]
 
Trick 3: Change color of prompt using tput command
You can also change color of the PS1 prompt using tput as shown below:


$ export PS1="\[$(tput bold)$(tput setb 4)$(tput setaf 7)\]\u@\h:\w $ \[$(tput sgr0)\]“
tput Color Capabilities:
  • tput setab [1-7] – Set a background color using ANSI escape
    • 

  • tput setb [1-7] – Set a background color
    • 

  • tput setaf [1-7] – Set a foreground color using ANSI escape
    • 

  • tput setf [1-7] – Set a foreground color
    • 

tput Text Mode Capabilities:
  • tput bold – Set bold mode
    • 

  • tput dim – turn on half-bright mode
    • 

  • tput smul – begin underline mode
    • 

  • tput rmul – exit underline mode
    • 

  • tput rev – Turn on reverse mode
    • 

  • tput smso – Enter standout mode (bold on rxvt)
    • 

  • tput rmso – Exit standout mode
    • 

  • tput sgr0 – Turn off all attributes
    • 

Color Code for tput:
  • 0 – Black
    • 

  • 1 – Red
    • 

  • 2 – Green
    • 

  • 3 – Yellow
    • 

  • 4 – Blue
    • 

  • 5 – Magenta
    • 

  • 6 – Cyan
    • 

  • 7 – White
    • 

Trick 4: Change the history file name using HISTFILE


By default, history is stored in ~/.bash_history file. Add the following line to the .bash_profile and relogin to the bash shell, to store the history command in .commandline_warrior file instead of .bash_history file. I’m yet to figure out a practical use for this. I can see this getting used when you want to track commands executed from different terminals using different history file name.


# vi ~/.bash_profile
HISTFILE=/root/.commandline_warrior





























Labels:
,
,
,



















0
comments:
        












Post a Comment






























2leep.com