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Keep bash input on top line of screen

Execute each command in terminal from top line / Execute clear before each commandPrinting (saving) the last bash input commandIs it possible to modify the colors in bash?Bash prompt that won't clobber long commandstmux status line with blank line on top?bash script taking inputHow to always print the prompt on a new line & keep inputKeep terminal input line at the top of the terminal?Have output and input in the same window in a Bash scriptMove terminal typed input to new line when console application/script displays output textSet PS1 based on the number of jobs

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ margin-bottom:0;
}

12

3

I'd like to keep the bash command prompt input at the top of the screen so that outputs from older commands are pushed downwards rather than up.

How can I achieve this?

terminal tty console stty virtual-consoles

share|improve this question

edited 17 mins ago

Tom Price

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

• 
  
  
  

  
  6
  

  
  
  
  
  
  

  
  
  So, if you cat a file, it would be reversed order?
  
  – chaos
  Jul 25 '15 at 17:50
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Nope, but I'd want the chunks of output to be pushed downwards
  
  – Tom Price
  Jul 26 '15 at 9:45
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  bash can't do this, because bash doesn't even know about screen positions: it just writes to an output file. You would need a terminal emulator that knows about bash's interactive prompt in order know when to reset the cursor and when to scroll the window.
  
  – chepner
  Mar 15 '17 at 1:54
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks @chepner, I'm revisiting this problem and your comment made me look outside of bash and start looking at the whole display stack. I want to remain within the text-based virtual consoles (i.e. no X Windows) so I'd be avoiding terminal emulators for now, but for my GUI sessions I'll certainly look into that. In case anyone comes across this question, my guess is it's to do with tty and I'm currently looking here for inspiration... linusakesson.net/programming/tty
  
  – Tom Price
  12 mins ago
  
  
  

  
  
  
  

add a comment | 

12

3

I'd like to keep the bash command prompt input at the top of the screen so that outputs from older commands are pushed downwards rather than up.

How can I achieve this?

terminal tty console stty virtual-consoles

share|improve this question

edited 17 mins ago

Tom Price

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

• 
  
  
  

  
  6
  

  
  
  
  
  
  

  
  
  So, if you cat a file, it would be reversed order?
  
  – chaos
  Jul 25 '15 at 17:50
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Nope, but I'd want the chunks of output to be pushed downwards
  
  – Tom Price
  Jul 26 '15 at 9:45
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  bash can't do this, because bash doesn't even know about screen positions: it just writes to an output file. You would need a terminal emulator that knows about bash's interactive prompt in order know when to reset the cursor and when to scroll the window.
  
  – chepner
  Mar 15 '17 at 1:54
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks @chepner, I'm revisiting this problem and your comment made me look outside of bash and start looking at the whole display stack. I want to remain within the text-based virtual consoles (i.e. no X Windows) so I'd be avoiding terminal emulators for now, but for my GUI sessions I'll certainly look into that. In case anyone comes across this question, my guess is it's to do with tty and I'm currently looking here for inspiration... linusakesson.net/programming/tty
  
  – Tom Price
  12 mins ago
  
  
  

  
  
  
  

add a comment | 

I'd like to keep the bash command prompt input at the top of the screen so that outputs from older commands are pushed downwards rather than up.

How can I achieve this?

terminal tty console stty virtual-consoles

share|improve this question

edited 17 mins ago

Tom Price

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

share|improve this question

edited 17 mins ago

Tom Price

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

share|improve this question

edited 17 mins ago

Tom Price

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

asked Jul 25 '15 at 17:06

Tom PriceTom Price

6877 bronze badges

1 Answer
1

active

oldest

votes

7

Add these lines to your .bashrc:

prompt_on_top() {

  tput cup 0 0

  tput el

  tput el1

}



pre_cmd() {

  if [ "$BASH_COMMAND" = "$PROMPT_COMMAND" ] || [ -n "$COMP_LINE" ]; then

    return

  fi

  printf "33[2J"

}



PROMPT_COMMAND="prompt_on_top"

trap 'pre_cmd' DEBUG

bash have PROMPT_COMMAND, which hold the command will be executed before bash show prompt. Here we set it to function prompt_on_top, which use tput to set the cursor at the top of screen.

bash also have a way to execute a command before executing any command, using trap to handle signal DEBUG. Here we set it to function pre_cmd, which will clear old screen, and do nothing if we did completion (COMP_LINE is not empty) or run command in BASH_PROMPT.

---

There's a limitation with this approach, if command output is too long too fit in a screen, then the output will be override by prompt_on_top action. In this case, you need to pipe the output to a pager to read the whole output.

share|improve this answer

edited Jul 26 '15 at 5:10

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Thanks for your well explained answer, there's a lot for me to read up on and learn. I've tested your script, and currently it effectively wipes the old output from the screen between commands. I'd like to keep the previous outputs on the screen, below the prompt, and have it so that new outputs are inserted between the prompt and the old output, therefore pushing the old output down the screen.
  
  – Tom Price
  Jul 26 '15 at 13:28
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  For those coming here via a web search, this code github.com/swirepe/alwaysontop also "keeps your bash prompt at the top of the screen", plus a couple of other functions. Does not answer the original question though: older command outputs are deleted as with cuonglm's code.
  
  – WillC
  Aug 1 '18 at 18:39
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  An other drawback of this solution, is that you don't have feedback on what command was last executed. That is, cat file will show file content, but you don't get an immediate feedback of the exact command executed. Ideally the prompt would be followed with an non-expanded + expanded version of the executed command, followed with the std ouput.
  
  – psychoslave
  Nov 22 '18 at 15:20
  

  
  
  
  

add a comment | 

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7

Add these lines to your .bashrc:

prompt_on_top() {

  tput cup 0 0

  tput el

  tput el1

}



pre_cmd() {

  if [ "$BASH_COMMAND" = "$PROMPT_COMMAND" ] || [ -n "$COMP_LINE" ]; then

    return

  fi

  printf "33[2J"

}



PROMPT_COMMAND="prompt_on_top"

trap 'pre_cmd' DEBUG

bash have PROMPT_COMMAND, which hold the command will be executed before bash show prompt. Here we set it to function prompt_on_top, which use tput to set the cursor at the top of screen.

bash also have a way to execute a command before executing any command, using trap to handle signal DEBUG. Here we set it to function pre_cmd, which will clear old screen, and do nothing if we did completion (COMP_LINE is not empty) or run command in BASH_PROMPT.

---

There's a limitation with this approach, if command output is too long too fit in a screen, then the output will be override by prompt_on_top action. In this case, you need to pipe the output to a pager to read the whole output.

share|improve this answer

edited Jul 26 '15 at 5:10

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Thanks for your well explained answer, there's a lot for me to read up on and learn. I've tested your script, and currently it effectively wipes the old output from the screen between commands. I'd like to keep the previous outputs on the screen, below the prompt, and have it so that new outputs are inserted between the prompt and the old output, therefore pushing the old output down the screen.
  
  – Tom Price
  Jul 26 '15 at 13:28
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  For those coming here via a web search, this code github.com/swirepe/alwaysontop also "keeps your bash prompt at the top of the screen", plus a couple of other functions. Does not answer the original question though: older command outputs are deleted as with cuonglm's code.
  
  – WillC
  Aug 1 '18 at 18:39
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  An other drawback of this solution, is that you don't have feedback on what command was last executed. That is, cat file will show file content, but you don't get an immediate feedback of the exact command executed. Ideally the prompt would be followed with an non-expanded + expanded version of the executed command, followed with the std ouput.
  
  – psychoslave
  Nov 22 '18 at 15:20
  

  
  
  
  

add a comment | 

7

Add these lines to your .bashrc:

prompt_on_top() {

  tput cup 0 0

  tput el

  tput el1

}



pre_cmd() {

  if [ "$BASH_COMMAND" = "$PROMPT_COMMAND" ] || [ -n "$COMP_LINE" ]; then

    return

  fi

  printf "33[2J"

}



PROMPT_COMMAND="prompt_on_top"

trap 'pre_cmd' DEBUG

bash have PROMPT_COMMAND, which hold the command will be executed before bash show prompt. Here we set it to function prompt_on_top, which use tput to set the cursor at the top of screen.

bash also have a way to execute a command before executing any command, using trap to handle signal DEBUG. Here we set it to function pre_cmd, which will clear old screen, and do nothing if we did completion (COMP_LINE is not empty) or run command in BASH_PROMPT.

---

There's a limitation with this approach, if command output is too long too fit in a screen, then the output will be override by prompt_on_top action. In this case, you need to pipe the output to a pager to read the whole output.

share|improve this answer

edited Jul 26 '15 at 5:10

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Thanks for your well explained answer, there's a lot for me to read up on and learn. I've tested your script, and currently it effectively wipes the old output from the screen between commands. I'd like to keep the previous outputs on the screen, below the prompt, and have it so that new outputs are inserted between the prompt and the old output, therefore pushing the old output down the screen.
  
  – Tom Price
  Jul 26 '15 at 13:28
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  For those coming here via a web search, this code github.com/swirepe/alwaysontop also "keeps your bash prompt at the top of the screen", plus a couple of other functions. Does not answer the original question though: older command outputs are deleted as with cuonglm's code.
  
  – WillC
  Aug 1 '18 at 18:39
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  An other drawback of this solution, is that you don't have feedback on what command was last executed. That is, cat file will show file content, but you don't get an immediate feedback of the exact command executed. Ideally the prompt would be followed with an non-expanded + expanded version of the executed command, followed with the std ouput.
  
  – psychoslave
  Nov 22 '18 at 15:20
  

  
  
  
  

add a comment | 

Add these lines to your .bashrc:

prompt_on_top() {

  tput cup 0 0

  tput el

  tput el1

}



pre_cmd() {

  if [ "$BASH_COMMAND" = "$PROMPT_COMMAND" ] || [ -n "$COMP_LINE" ]; then

    return

  fi

  printf "33[2J"

}



PROMPT_COMMAND="prompt_on_top"

trap 'pre_cmd' DEBUG

bash have PROMPT_COMMAND, which hold the command will be executed before bash show prompt. Here we set it to function prompt_on_top, which use tput to set the cursor at the top of screen.

bash also have a way to execute a command before executing any command, using trap to handle signal DEBUG. Here we set it to function pre_cmd, which will clear old screen, and do nothing if we did completion (COMP_LINE is not empty) or run command in BASH_PROMPT.

---

There's a limitation with this approach, if command output is too long too fit in a screen, then the output will be override by prompt_on_top action. In this case, you need to pipe the output to a pager to read the whole output.

share|improve this answer

edited Jul 26 '15 at 5:10

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges

prompt_on_top() {

  tput cup 0 0

  tput el

  tput el1

}



pre_cmd() {

  if [ "$BASH_COMMAND" = "$PROMPT_COMMAND" ] || [ -n "$COMP_LINE" ]; then

    return

  fi

  printf "33[2J"

}



PROMPT_COMMAND="prompt_on_top"

trap 'pre_cmd' DEBUG

share|improve this answer

edited Jul 26 '15 at 5:10

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges

answered Jul 25 '15 at 17:45

cuonglmcuonglm

108k2626 gold badges221221 silver badges322322 bronze badges