Shell History

FluidShell provides you the capability to view (and execute) previously executed shell commands.

This feature is accomplished by implementing a user friendly history command (similar to the Bash "history" command).

For instance to view all the previously executed commands, type history at the FluidShell prompt;

:$ history
   1  history
   2  \help
   3  export | grep HIST
   4  export HISTCONTROL=$HISTCONTROL:"ignorespace "
   5  export | grep HIST
   6  \help
   7  history
   8  clear
   9  sqlhistory
  10  echo $HISTCONTROL
  11  pwd
  12  history
  13  ls
  14  sendmail
  15  export HISTFILE=C:\\Users\\vikram\\.datastudio\\connections\\vikram.history
  16  clear
  17  history

The shell variables which provide control options to this command can be viewed as follows:

:$ export | grep HIST
declare -x CLI_SHELL_LINE_INTERPRETER_EVAL_HISTORY="true"
declare -x HISTCONTROL="ignoredups:ignorespace"
declare -x HISTFILE="C:\\Users\\vikram\\.datastudio\\connections\\MSSQL Server 2012 on Ferenganar.history"
declare -x HISTFILESIZE="500"
declare -x HISTSIZE="500"

CLI_SHELL_LINE_INTERPRETER_EVAL_HISTORY

CLI_SHELL_LINE_INTERPRETER_EVAL_HISTORY defines whether command history expansion via !<#> (<#> is a number or string), will take place or not. If this value is set to "false", then !<#> is not expanded; it's treated as a literal.

HISTCONTROL

HISTCONTROL variable allows you to control how FluidShell stores your command history. You can tell it to ignore duplicate commands and/or to ignore commands that have leading whitespaces. This is especially useful since we tend to use some commands multiple number of times. These duplicate commands can fill up the command history pretty fast, crowding the ones we really might need. We can use the "ignoredups" (default) to ignore duplicate commands.

For example:

:$ history
 1 history
 2 export | grep HIST

:$ pwd
 C:/Users/vikram

:$ pwd
 C:/Users/vikram

:$ pwd
 C:/Users/vikram

:$ history
 1 history
 2 export | grep HIST
 3 pwd  << This command had duplicates and has come only once.
 4 history

Note: "ignoredups" will only ignore immediately executed duplicate commands.

We can use "ignorespace" (default) control option to ignore commands that start with space; this is useful when we don't want to record a particular command in the command history. Just add a space at the beginning of the line and the command will not be saved in history.

A third value "ignoreboth" is also supported and is a shorthand for both "ignorespace" and "ignoredups".

HISTFILE

At a physical level, shell command history is stored on a per database server connection basis and is written to <user_home>/.datastudio/connections/.history file when FluidShell exits. If no database server connection is associated with a FluidShell, then the history is stored within the <user_home>/.datastudio/shell.history file. HISTFILE variable allows you to choose a different physical file for storing the command history than the default one (.history).

HISTFILESIZE

HISTFILESIZE variable defines the maximum number of commands that will be retained (in the physical file) by FluidShell when it exits. By default, this value is set to "500" (implying previous 500 commands will be stored and available as history at next start up of the FluidShell).

HISTSIZE

HISTSIZE variable defines the maximum number of commands that will be retained in memory by FluidShell during its run. By default this value is set to "500" (implying previous 500 commands will be stored and available as history during the life time of a FluidShell).

Please note that HISTFILESIZE pertains to the physical storage of command history where as HISTFILE pertains to in-memory storage of command history.

History command usage

1. You can view all the previously executed commands using the history command.

:$ history
   1  history
   2  \help
   3  export | grep HIST
   4  export HISTCONTROL=$HISTCONTROL:"ignorespace "
   5  export | grep HIST
   6  \help
   7  history
   8  clear
   9  sqlhistory
  10  echo $HISTCONTROL
  11  pwd
  12  history
  13  ls
  14  sendmail
  15  export HISTFILE=C:\\Users\\vikram\\.datastudio\\connections\\vikram.history
  16  clear
  17  history

You can also filter command history using pipeling and grep such as:

:$ history | grep "export"
   2  export grep HIST
   3  export | grep HIST
   4  export HISTCONTROL=$HISTCONTROL:"erasedups "
   5  export | grep HIST
  15  export HISTFILE=C:\\Users\\vikram\\.datastudio\\connections\\vikram.history
  22  history | grep "export"

:$ history | more
    1  history
    2  \help
    3  export | grep HIST
    4  export HISTCONTROL=$HISTCONTROL:"ignorespace "
    5  export | grep HIST
    6  \help
    7  history
    8  clear
    9  sqlhistory
   10  echo $HISTCONTROL
   .
   .
   .
   (paginated ...)
   .
   .
   .
   111  pwd
   112  history
   113  ls
   114  sendmail
   115  export HISTFILE=C:\\Users\\vikram\\.datastudio\\connections\\vikram.history
   116  clear
   117  history | more

2. You can also execute a previous command using the following options:

a) !! to execute the last command in command history.

For instance:

:$ pwd
C:/Users/vikram

:$ !!
pwd
C:/Users/vikram

b) !<number> where <number> is the index of a command in the command history. For instance to repeat "\help" command:

:$ !6
 \help
alias  ask  autocommit  cat  cd  change  clear   cli  commit  compare  connect   cp  csv2excel csv2html  csv2json  csv2xml  declare  
describe disconnect  echo  erm  exec  export fluidshell  go  grep  gunzip  gzip    help    history    list    ls      mkdir   more    mv  
open    pwd   reconnect  ren  rm  rmdir   rollback   run   scp   sendmail   session  sleep   source  sqlbuffer sqldump   sqlexport  
sqlhistory  sqlimport  ssh  syncdir  tail  tar  tee  touch   unalias unset   unzip   zip

Please note using a negative number is permissible and is taken as the index from the last command entry. For instance executing:

:$  history
   1  history
   2  \help
   3  export | grep HIST
   4  export HISTCONTROL=$HISTCONTROL:"ignorespace "
   5  export | grep HIST
   6  \help
   7  history
   8  clear
   9  sqlhistory
  10  echo $HISTCONTROL
  11  pwd
  12  history
  13  ls
  14  sendmail
  15  export HISTFILE=C:\\Users\\vikram\\.datastudio\\connections\\vikram.history
  16  clear
  17  history

:$ !-4
Sendmail
Usage: sendmail [OPTION...] ADDRESS...
Try "\help sendmail" for more information.

c) !<string> where <string> is the initial sequence of this command. Such as:

:$ !se
Sendmail
Usage: sendmail [OPTION...] ADDRESS...
Try "\help sendmail" for more information.

Please note that this will execute the most recent command starting with this sequence.

d) !? executes the most recent command containing the string . Such as:

:$ !?more
history | more
   1  history
   2  \help
   3  export | grep HIST
   4  export HISTCONTROL=$HISTCONTROL:"ignorespace "
   5  export | grep HIST
   6  \help
   7  history | more
   8  clear
   9  sqlhistory
  10  echo $HISTCONTROL
  11  pwd
  12  history
  13  ls
  14  sendmail
  15  export HISTFILE=C:\\Users\\vikram\\.datastudio\\connections\\vikram.history
  16  clear
  17  history | more

3. Using history –c command clears all the existing history (new history will still get created) in the current FluidShell. Please note that since the in-memory command history will be deleted by this command, those deleted commands as such will also not appear in the FluidShell history file (database server connection.history) for the current database server connection.

You can customize Shell history command for a server connection or the global FluidShell by configuring the HIST???? options and adding them to the FluidShell initialization script via Server Registration->FluidShell and/or File->Options->FluidShell->Script.

For instance adding export HISTSIZE=999 to the startup script will make sure that the current shell has in-memory capacity of storing last 999 commands.