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It is fairly easy to write a GRASS job as Shell script which launches GRASS, does the operation and cleans up the temporary files.
+
This page contains information about GRASS GIS' own shell setup and use.  
  
=== What's this? ===
+
For information about scripting for GRASS, please refer to the page [http://grasswiki.osgeo.org/wiki/Shell_scripting Shell scripting].
  
Often it is convenient to automate repeated jobs. GRASS can be controlled via user scripts to facilitate daily work.
+
== Automated batch jobs: Setting the GRASS environmental variables ==
How to start? Using command line is a kind of writing scripts without saving them - so, you may start to write
 
'''your first script''' by saving the executed commands in a text file (use your preferred editor to do so, ideally
 
save the script file in ASCII format).
 
  
=== A first script ===
+
'''''Main article: [[Working with GRASS without starting it explicitly]]'''''
  
Comments should be started with a '#' character. The first line indicates the shell interpreter to be used, here "sh" which is always in the /bin/ directory.
+
This section applies to jobs which shall set the entire GRASS environment.
 
+
You have to set a couple of variables to enable GRASS command to run from outside GRASS:
Silly example:
 
 
 
  #!/bin/sh
 
  # my first script
 
 
 
  # plot current region settings
 
  g.region -p
 
 
 
  # leave with exit status 0 which means "ok":
 
  exit 0
 
 
 
Save this in a file "myscript.sh" and run it within GRASS GIS from the command line:
 
 
 
  sh myscript.sh
 
 
 
It should print the current region settings and finish.
 
 
 
=== Setting the variables ===
 
 
 
You have to set a couple of variables to enable GRASS command to run (see ''''GRASS Batch jobs'''' below for easier solution!).
 
 
 
''[http://article.gmane.org/gmane.comp.gis.grass.user/17980 See this post] to the mailing list. Proabably need to update this wiki page with that information.''
 
  
 +
<source lang="bash">
 
   # Example in bash shell syntax:
 
   # Example in bash shell syntax:
 
   
 
   
 
   # path to GRASS binaries and libraries:
 
   # path to GRASS binaries and libraries:
   export GISBASE=/usr/local/grass64
+
   export GISBASE=/usr/lib64/grass78
 
   
 
   
 
   export PATH=$PATH:$GISBASE/bin:$GISBASE/scripts
 
   export PATH=$PATH:$GISBASE/bin:$GISBASE/scripts
 
   export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$GISBASE/lib
 
   export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$GISBASE/lib
 +
 
 +
  # set PYTHONPATH to include the GRASS Python lib
 +
  if [ ! "$PYTHONPATH" ] ; then
 +
      PYTHONPATH="$GISBASE/etc/python"
 +
  else
 +
      PYTHONPATH="$GISBASE/etc/python:$PYTHONPATH"
 +
  fi
 +
  export PYTHONPATH
 
   
 
   
 
   # use process ID (PID) as lock file number:
 
   # use process ID (PID) as lock file number:
Line 52: Line 36:
 
   export GRASS_HEIGHT=1200
 
   export GRASS_HEIGHT=1200
 
   export GRASS_PNG_COMPRESSION=1
 
   export GRASS_PNG_COMPRESSION=1
 +
  export GRASS_MESSAGE_FORMAT=plain
 +
</source>
 +
 +
Define a GRASS session with the last used GISDBASE, LOCATION_NAME, and MAPSET
  
  
The following variable defines where the GRASS settings file is stored. This can be anywhere on the system. You could also generate the '.grassrc6' on the fly in your script, even with different name. Just indicate it correctly:
+
<source lang="bash">
 +
  # path to GRASS settings file
 +
  export GISRC=$HOME/.grassrc7
 +
</source>
 +
 
 +
Define a GRASS session with a different GISDBASE, LOCATION_NAME, and/or MAPSET
  
 +
<source lang="bash">
 
   # path to GRASS settings file
 
   # path to GRASS settings file
   export GISRC=$HOME/.grassrc6
+
   export GISRC=/tmp/grass7-${USER}-$GIS_LOCK/gisrc
 +
  # remove any leftover files/folder
 +
  rm -fr /tmp/grass7-${USER}-$GIS_LOCK
 +
  mkdir /tmp/grass7-${USER}-$GIS_LOCK
 +
  export TMPDIR="/tmp/grass7-${USER}-$GIS_LOCK"
 +
  # set GISDBASE, LOCATION_NAME, and/or MAPSET
 +
  echo "GISDBASE: /path/to/some/grassdata" >>$GISRC
 +
  echo "LOCATION_NAME: some_location" >>$GISRC
 +
  echo "MAPSET: some_mapset" >>$GISRC
 +
  # start in text mode
 +
  echo "GRASS_GUI: text" >>$GISRC
 +
</source>
 +
 
 +
The following three settings are only recommended if you will be calling the script from another program - e.g. a PHP web page using system() or exec()
 +
 
 +
<source lang="bash">
 +
  export HOME=/var/www
 +
  export USER=www-data
 +
  export GROUP=www-data
 +
</source>
  
 
Now you can test:
 
Now you can test:
  
 +
<source lang="bash">
 
   # this should print the GRASS version used:
 
   # this should print the GRASS version used:
 
   g.version
 
   g.version
 +
  # check GISDBASE, LOCATION_NAME, and MAPSET
 +
  g.gisenv
 
   # other calculations go here ...
 
   # other calculations go here ...
 +
</source>
 +
 +
If this works, you can launch other GRASS commands. The approach works within Shell scripts and also in the command line terminal.
  
You should cleanup internal tmp files like this:
+
When done, you should cleanup internal tmp files like this:
  
 +
<source lang="bash">
 
   # run GRASS' cleanup routine
 
   # run GRASS' cleanup routine
 
   $GISBASE/etc/clean_temp
 
   $GISBASE/etc/clean_temp
 
   
 
   
 
   # remove session tmp directory:
 
   # remove session tmp directory:
   rm -rf /tmp/grass6-$USER-$GIS_LOCK
+
   rm -rf /tmp/grass7-${USER}-$GIS_LOCK
 +
</source>
  
If this works, you can launch other GRASS commands. The approach works within Shell scripts and also in the command line terminal.
+
'''Changing the prompt:'''
 +
 
 +
<source lang="bash">
 +
  PS1_BACKUP="$PS1"
 +
  export PS1="GRASS 6> "
 +
</source>
 +
 
 +
Once you are done, you can set it back (see also next hint about unsetting variables):
 +
 
 +
<source lang="bash">
 +
  export PS1="$PS1_BACKUP"
 +
</source>
 +
 
 +
'''Unsetting variables after usage:'''
 +
 
 +
<source lang="bash">
 +
  Using the "unset VARNAME" command you get rid of it:
 +
  unset GISBASE
 +
  unset GISRC
 +
  ...
 +
</source>
  
 
=== Example ===
 
=== Example ===
  
* GRASS shell script job to generate a [http://grass.osgeo.org/spearfish/php_grass_earthquakes.php Recent Earthquakes Map]
+
* GRASS shell script job to generate a [http://grass.fbk.eu/spearfish/php_grass_earthquakes.php Recent Earthquakes Map] (get the [http://grass.fbk.eu/spearfish/grass_earthquakes.sh grass_earthquakes.sh shell script])
: ({{website|spearfish/grass_earthquakes.sh|grass_earthquakes.sh shell script}})
 
  
 
=== Parallel GRASS jobs ===
 
=== Parallel GRASS jobs ===
  
See [[Parallel GRASS jobs]] for openMosix, PBS etc.
+
See [[Parallel GRASS jobs]] for Grid Engine, PBS etc.
  
 
=== GRASS Batch jobs ===
 
=== GRASS Batch jobs ===
  
There is (now) an alternative method to easily run jobs in GRASS from a collection of commands in a shell script file. Just define the environmental variable GRASS_BATCH_JOB with the shell script file containing GRASS (or whatever) commands, preferably with full path. Then launch GRASS and it will be executed. It is best to launch GRASS in -text mode and to provide GISDBASE/location/mapset as parameters. The job script needs executable file permissions (chmod).
+
Since GRASS GIS 6.4, there is an alternative method to easily run jobs in GRASS from a collection of commands in a shell script file. Just define the environmental variable GRASS_BATCH_JOB with the shell script file containing GRASS (or whatever) commands, preferably with full path. Then launch GRASS and it will be executed. It is best to launch GRASS in <tt>-text</tt> mode and to provide gisdbase/location/mapset as parameters. The job script needs executable file permissions (<tt>chmod</tt> on Unix). In order to get readable percentage output during the processing (0..2..4... 100%), we set the environment variable GRASS_MESSAGE_FORMAT to "plain":
  
 
Example:
 
Example:
  
      chmod u+x $HOME/my_grassjob.sh
+
<source lang="bash">
      export GRASS_BATCH_JOB=$HOME/my_grassjob.sh
+
#### 1) PREPARATION
      grass64 ~/grassdata/spearfish60/neteler/
+
# First we generate a script which contains the command(s) to be executed:
 +
# for convenience, we save the file in our HOME directory
 +
## You may use also a text editor for this, here we use the "echo" shell command
 +
 
 +
echo "export GRASS_MESSAGE_FORMAT=plain
 +
# set computational region, here: UTM32N coordinates
 +
g.region n=4900000 s=4800000 w=700000 e=800000 res=100
 +
v.random mymap3000 n=3000
 +
v.out.ogr input=mymap3000 output=mymap3000.shp" > $HOME/my_grassjob.sh
  
The grass64 command starts GRASS in the given mapset, executes the contents of the job file and leaves GRASS. Since the normal startup/closure is used, all tmp files are properly removed.
+
# verify the content of the file
 +
cat $HOME/my_grassjob.sh
  
Note: The $HOME variable (or the ~ shortcut) cannot be used in the batch job since the variables are not available here.
+
# make it user executable (this is important, use 'chmod' or via file manager)
 +
chmod u+x $HOME/my_grassjob.sh
  
To deactivate the batch job mode, run (bash example):
+
# create a directory (may be elsewhere) to hold the location used for processing
 +
mkdir -p $HOME/grassdata
  
        unset GRASS_BATCH_JOB
+
# create new temporary location for the job, exit after creation of this location
 +
grass78 -c epsg:32632 $HOME/grassdata/mytemploc_utm32n -e
 +
 
 +
#### 2) USING THE BATCH JOB
 +
# define job file as environmental variable
 +
export GRASS_BATCH_JOB="$HOME/my_grassjob.sh"
 +
 
 +
# now we can use this new location and run the job defined via GRASS_BATCH_JOB
 +
grass78 $HOME/grassdata/mytemploc_utm32n/PERMANENT
 +
 
 +
#### 3) CLEANUP
 +
# switch back to interactive mode, for the next GRASS GIS session
 +
unset GRASS_BATCH_JOB
 +
 
 +
# delete temporary location (consider to export results first in your batch job)
 +
rm -rf $HOME/grassdata/mytemploc_utm32n
 +
 
 +
# Now you can use the resulting SHAPE file "mymap3000.shp" elsewhere.
 +
</source>
 +
 
 +
The grass78 command starts GRASS in the given mapset, executes the contents of the job file and leaves GRASS. Since the normal startup/closure is used, all internal tmp files are properly removed.
 +
 
 +
Note: The $HOME variable (or the ~ shortcut) cannot be used in the batch job itself since the variables are not available here.
 +
 
 +
==== Example ====
 +
 
 +
* Another set of GRASS shell scripts to run the job to generate another version of the [http://adhoc.osgeo.osuosl.org/grass/alternate_projections/earthquakes_wintri.png Recent Earthquakes Map] (find the setup files in the [https://trac.osgeo.org/grass/browser/grass-promo/tutorials/batch_processing "batch_processing" tutorials section] of the GRASS SVN)
  
 
=== Unattended execution ===
 
=== Unattended execution ===
 +
 +
* {{wikipedia|GNU_Screen}} is another ''extremely'' valuable tool if you need to detatch and leave long-running processes unattended. It is well worth your time to learn how to use it if you run scripts on remote systems. There are many good tutorials on the web.
 +
: Usage:
 +
:: Run "screen" in the terminal. You will reach again the command line but now in screen mode. Now start GRASS.
 +
::: - To disconnect from the session press Control-A, Control-D.
 +
::: - To list your screens type "screen -ls" (to find it back)
 +
::: - To reconnect with a disconnected screen run "screen -r [identifier]" (the "identifier" you need only if you have several screens running)
 +
:: Enjoy.
  
 
* Along with the "{{wikipedia|nohup}}" (no hang-up) command you can login to your machine, launch the job and leave the machine again.  
 
* Along with the "{{wikipedia|nohup}}" (no hang-up) command you can login to your machine, launch the job and leave the machine again.  
 
The process will continue after you logged off when you start it with nohup:
 
The process will continue after you logged off when you start it with nohup:
 
         nohup grass64 ~/grassdata/spearfish60/neteler/ &
 
         nohup grass64 ~/grassdata/spearfish60/neteler/ &
 
* {{wikipedia|GNU_Screen}} is another ''extremely'' valuable tool if you need to detatch and leave long-running processes unattended. It is well worth your time to learn how to use it if you run scripts on remote systems. There are many good tutorials on the web.
 
  
 
=== Receive a notification when finished ===
 
=== Receive a notification when finished ===
Line 123: Line 206:
 
         EOF
 
         EOF
  
=== See also ===
+
or simply like this:
 +
        echo "GRASS GIS has finished the batch job $0" | mail -s "GRASS job finished" me@mydomain.org
 +
 
 +
== Stupid pet tricks (don't use them!) ==
 +
 
 +
Note: This is highly discouraged. Keep fingers off from manually modifying the content of a GRASS GIS mapset (at least don't complain if you break things).
 +
 
 +
<strike>;Quick cd to the MAPSET directory
 +
To make a quick little function called 'g.cd' to change into the mapset dir, add this to <tt>~/.grass.bashrc</tt>:
 +
 
 +
<source lang="bash">
 +
g.cd()
 +
{
 +
  MAPSET=`g.gisenv get=MAPSET`
 +
  LOCATION_NAME=`g.gisenv get=LOCATION_NAME`
 +
  GISDBASE=`g.gisenv get=GISDBASE`
 +
  LOCATION="$GISDBASE/$LOCATION_NAME/$MAPSET"
 +
  cd "$LOCATION/$1"
 +
}
 +
</source>
 +
 
 +
With that you can also do like: "<tt>g.cd colr/</tt>" to get to the color tables directory, or "<tt>g.cd ..</tt>" to get to the LOCATION directory.
 +
 
 +
Another method would be
 +
<source lang="bash">
 +
  alias g.home='cd `dirname "$HISTFILE"`'
 +
</source>
 +
</strike>
 +
 
 +
;Simpler command completion from command history
 +
 
 +
Add this to a file called <tt>~/.inputrc</tt> in your home dir:
 +
 
 +
<source lang="bash">
 +
set prefer-visible-bell
 +
 
 +
# -------- Bind page up/down wih history search ---------
 +
"\e[5~": history-search-backward
 +
"\e[6~": history-search-forward
 +
</source>
 +
 
 +
Then you can type a bit of a command and use PgUp and PgDn to cycle through the command history which matches in a way less clumsy that Ctrl-r. Also it tells to make the shell flash on alarm instead of sending a beep to the speaker (making tab-completion compatible with your office mates).
 +
 
 +
== See also ==
 +
 
 +
Generic Shell script tutorials:
 +
* [http://tldp.org/LDP/abs/abs-guide.pdf Advance bash-scripting guide]
 +
* [http://www.linuxconfig.org/Bash_scripting_Tutorial Bash scripting Tutorial]
 +
 
 +
GRASS Shell script tutorials:
 +
* [http://www.grassbook.org/examples_menu3rd.php GRASS Book script examples]
 +
* [http://www.grassbook.org/unix_commands_table.php List of important UNIX system commands]
  
 +
Misc:
 +
* [[Script portability]]
 
* Other GRASS environment {{cmd|variables}}
 
* Other GRASS environment {{cmd|variables}}
* [[GRASS_and_Python#Python-SWIG-GRASS_interface|SWIG bindings]] (Python/Perl/etc)
+
* [[GRASS and Python]]
* Advance bash-scripting guide [http://tldp.org/LDP/abs/abs-guide.pdf]
+
* [[Working with GRASS without starting it explicitly]]
 +
* [[GRASS and windows console]]
  
 
[[Category:FAQ]]
 
[[Category:FAQ]]
 +
[[Category:Scripting]]
 
[[Category:Linking to other languages]]
 
[[Category:Linking to other languages]]

Latest revision as of 06:29, 29 March 2021

This page contains information about GRASS GIS' own shell setup and use.

For information about scripting for GRASS, please refer to the page Shell scripting.

Automated batch jobs: Setting the GRASS environmental variables

Main article: Working with GRASS without starting it explicitly

This section applies to jobs which shall set the entire GRASS environment. You have to set a couple of variables to enable GRASS command to run from outside GRASS:

   # Example in bash shell syntax:
 
   # path to GRASS binaries and libraries:
   export GISBASE=/usr/lib64/grass78
 
   export PATH=$PATH:$GISBASE/bin:$GISBASE/scripts
   export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$GISBASE/lib
   
   # set PYTHONPATH to include the GRASS Python lib
   if [ ! "$PYTHONPATH" ] ; then
      PYTHONPATH="$GISBASE/etc/python"
   else
      PYTHONPATH="$GISBASE/etc/python:$PYTHONPATH"
   fi
   export PYTHONPATH
 
   # use process ID (PID) as lock file number:
   export GIS_LOCK=$$
 
   # settings for graphical output to PNG file (optional)
   export GRASS_PNGFILE=/tmp/grass6output.png
   export GRASS_TRUECOLOR=TRUE
   export GRASS_WIDTH=900
   export GRASS_HEIGHT=1200
   export GRASS_PNG_COMPRESSION=1
   export GRASS_MESSAGE_FORMAT=plain

Define a GRASS session with the last used GISDBASE, LOCATION_NAME, and MAPSET


   # path to GRASS settings file
   export GISRC=$HOME/.grassrc7

Define a GRASS session with a different GISDBASE, LOCATION_NAME, and/or MAPSET

   # path to GRASS settings file
   export GISRC=/tmp/grass7-${USER}-$GIS_LOCK/gisrc
   # remove any leftover files/folder
   rm -fr /tmp/grass7-${USER}-$GIS_LOCK
   mkdir /tmp/grass7-${USER}-$GIS_LOCK
   export TMPDIR="/tmp/grass7-${USER}-$GIS_LOCK"
   # set GISDBASE, LOCATION_NAME, and/or MAPSET
   echo "GISDBASE: /path/to/some/grassdata" >>$GISRC
   echo "LOCATION_NAME: some_location" >>$GISRC
   echo "MAPSET: some_mapset" >>$GISRC
   # start in text mode
   echo "GRASS_GUI: text" >>$GISRC

The following three settings are only recommended if you will be calling the script from another program - e.g. a PHP web page using system() or exec()

   export HOME=/var/www
   export USER=www-data
   export GROUP=www-data

Now you can test:

   # this should print the GRASS version used:
   g.version
   # check GISDBASE, LOCATION_NAME, and MAPSET
   g.gisenv
   # other calculations go here ...

If this works, you can launch other GRASS commands. The approach works within Shell scripts and also in the command line terminal.

When done, you should cleanup internal tmp files like this:

   # run GRASS' cleanup routine
   $GISBASE/etc/clean_temp
 
   # remove session tmp directory:
   rm -rf /tmp/grass7-${USER}-$GIS_LOCK

Changing the prompt:

   PS1_BACKUP="$PS1"
   export PS1="GRASS 6> "

Once you are done, you can set it back (see also next hint about unsetting variables):

   export PS1="$PS1_BACKUP"

Unsetting variables after usage:

   Using the "unset VARNAME" command you get rid of it:
   unset GISBASE
   unset GISRC
   ...

Example

Parallel GRASS jobs

See Parallel GRASS jobs for Grid Engine, PBS etc.

GRASS Batch jobs

Since GRASS GIS 6.4, there is an alternative method to easily run jobs in GRASS from a collection of commands in a shell script file. Just define the environmental variable GRASS_BATCH_JOB with the shell script file containing GRASS (or whatever) commands, preferably with full path. Then launch GRASS and it will be executed. It is best to launch GRASS in -text mode and to provide gisdbase/location/mapset as parameters. The job script needs executable file permissions (chmod on Unix). In order to get readable percentage output during the processing (0..2..4... 100%), we set the environment variable GRASS_MESSAGE_FORMAT to "plain":

Example:

#### 1) PREPARATION
# First we generate a script which contains the command(s) to be executed:
# for convenience, we save the file in our HOME directory
## You may use also a text editor for this, here we use the "echo" shell command

echo "export GRASS_MESSAGE_FORMAT=plain
# set computational region, here: UTM32N coordinates
g.region n=4900000 s=4800000 w=700000 e=800000 res=100
v.random mymap3000 n=3000
v.out.ogr input=mymap3000 output=mymap3000.shp" > $HOME/my_grassjob.sh

# verify the content of the file
cat $HOME/my_grassjob.sh

# make it user executable (this is important, use 'chmod' or via file manager)
chmod u+x $HOME/my_grassjob.sh

# create a directory (may be elsewhere) to hold the location used for processing
mkdir -p $HOME/grassdata

# create new temporary location for the job, exit after creation of this location
grass78 -c epsg:32632 $HOME/grassdata/mytemploc_utm32n -e

#### 2) USING THE BATCH JOB
# define job file as environmental variable
export GRASS_BATCH_JOB="$HOME/my_grassjob.sh"

# now we can use this new location and run the job defined via GRASS_BATCH_JOB
grass78 $HOME/grassdata/mytemploc_utm32n/PERMANENT

#### 3) CLEANUP
# switch back to interactive mode, for the next GRASS GIS session
unset GRASS_BATCH_JOB

# delete temporary location (consider to export results first in your batch job)
rm -rf $HOME/grassdata/mytemploc_utm32n

# Now you can use the resulting SHAPE file "mymap3000.shp" elsewhere.

The grass78 command starts GRASS in the given mapset, executes the contents of the job file and leaves GRASS. Since the normal startup/closure is used, all internal tmp files are properly removed.

Note: The $HOME variable (or the ~ shortcut) cannot be used in the batch job itself since the variables are not available here.

Example

Unattended execution

  • GNU_Screen is another extremely valuable tool if you need to detatch and leave long-running processes unattended. It is well worth your time to learn how to use it if you run scripts on remote systems. There are many good tutorials on the web.
Usage:
Run "screen" in the terminal. You will reach again the command line but now in screen mode. Now start GRASS.
- To disconnect from the session press Control-A, Control-D.
- To list your screens type "screen -ls" (to find it back)
- To reconnect with a disconnected screen run "screen -r [identifier]" (the "identifier" you need only if you have several screens running)
Enjoy.
  • Along with the "nohup" (no hang-up) command you can login to your machine, launch the job and leave the machine again.

The process will continue after you logged off when you start it with nohup:

       nohup grass64 ~/grassdata/spearfish60/neteler/ &

Receive a notification when finished

Maybe put email notification at the end of 'my_grassjob.sh' using the "mail" or the "mutt" program, for example like this:

       echo "Finished at `date`" > /tmp/done.txt && \
       EDITOR=touch mutt -s "Job done" \
       me@mydomain.org < /tmp/done.txt && rm -f /tmp/done.txt

or like this:

       mail -s "GRASS job $0 finished" me@mydomain.org <<EOF
         GRASS GIS has finished the batch job $0
       EOF

or simply like this:

       echo "GRASS GIS has finished the batch job $0" | mail -s "GRASS job finished" me@mydomain.org

Stupid pet tricks (don't use them!)

Note: This is highly discouraged. Keep fingers off from manually modifying the content of a GRASS GIS mapset (at least don't complain if you break things).

;Quick cd to the MAPSET directory To make a quick little function called 'g.cd' to change into the mapset dir, add this to ~/.grass.bashrc:

g.cd()
{
  MAPSET=`g.gisenv get=MAPSET`
  LOCATION_NAME=`g.gisenv get=LOCATION_NAME`
  GISDBASE=`g.gisenv get=GISDBASE`
  LOCATION="$GISDBASE/$LOCATION_NAME/$MAPSET"
  cd "$LOCATION/$1"
}

With that you can also do like: "g.cd colr/" to get to the color tables directory, or "g.cd .." to get to the LOCATION directory.

Another method would be

  alias g.home='cd `dirname "$HISTFILE"`'

Simpler command completion from command history

Add this to a file called ~/.inputrc in your home dir:

set prefer-visible-bell

# -------- Bind page up/down wih history search ---------
"\e[5~": history-search-backward
"\e[6~": history-search-forward

Then you can type a bit of a command and use PgUp and PgDn to cycle through the command history which matches in a way less clumsy that Ctrl-r. Also it tells to make the shell flash on alarm instead of sending a beep to the speaker (making tab-completion compatible with your office mates).

See also

Generic Shell script tutorials:

GRASS Shell script tutorials:

Misc: