[ale] command doesn't work from script, only command line...

[Keith Hopkins]

Christopher Bergeron wrote:

> Does anyone know why this command:
> 
> cd `history | grep cd | grep -v grep | tail -n 2 | tail -n 1 | tr -s " " |
> cut -f 4 -d " "`
> 
> works from the command line, but not from a [verbatim] shell script:
> #!/bin/bash
> cd `history | grep cd | grep -v grep | tail -n 2 | tail -n 1 | tr -s " " |
> cut -f 4 -d " "`
> 
> I just named it p (for Previous) so I can switch to the directory I just
> came from.  It doesn't work though.  Any suggestions?
> 


Hi Christopher,

   It doesn't work for a couple of reasons.

1 (most importantly), a script forks a new process, and it does not inherit the parent's history.  To verify this, just run a script only containing the history command.  It will return nothing.
   Try putting it in an alias instead of a script.  That way it will run in the current shell process.

2) I think your second "tail" should actually be "head".


Lost in Tokyo,
   Keith



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