HISTCMD in bash 3.2.17


 
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# 1  
Old 07-15-2009
HISTCMD in bash 3.2.17

I'm learning about some shell variables and can't get anything about HISTCMD - message says 'command not found.' I'm assuming that it doesn't exist in this version, correct? (I'm using a book that was written in 2005). Just got the same result with HISTIGNORE. Any others?

Last edited by Straitsfan; 07-15-2009 at 08:01 PM..
# 2  
Old 07-16-2009
Command in Unix are not normally all in CAPITAL letters, environment variables can be, suggest taking a look at:
history(3): GNU History Library - Linux man page
and
fc

My use of history does not go beyond increasing the HISTSIZE (an environment variable), running the history command to list previously run commands and using !nnn, where nnn is the number of the entry in the history to run that command again.
# 3  
Old 07-16-2009
Thanks. HISTCMD is all caps because it's a shell variable (my man page on bash has it as all caps).
# 4  
Old 07-20-2009
The HISTCMD variable is evidently used to keep track of what the next history number entry will be:
Code:
$ fc -l
489     ls
490     cd Pictures/
491     cd Pictures/
492     ls
493     du -sh ./*
494     cd ./200907_July
495     du -sh ./*
496     cd ../200906_June
497     du -sh ./*
498     cd ../200905_May
499     du -sh ./*
500     man bash
501     ls
502     fc -l
503     echo $HISTCMD
504     history
$ echo $HISTCMD
507
$ history | tail -6
  502  fc -l
  503  echo $HISTCMD
  504  history
  505  fc -l
  506  echo $HISTCMD
  507  history | tail -6
$

So you can check what it is set to, but cannot run it unlike:
Code:
$ !501

Which select a command run in the past (ls in this example).
 
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