topic Re: grep and | in Operating System - Linux

grep and |

Markus Pöstinger — Wed, 22 Aug 2007 03:45:57 GMT

Hi there,

I need some help with the grep-Command in combination with the logical OR '|'. The following expression does not work correctly. It should recognize all correct dates in the form MMYYYY between 012000 and 122019.

grep "^$1[0-2]$\|$0[1-9]$20[0-1][0-9]$"

The problem is definitely the |. I tried it with or without the \, but it does not make any difference. I am using it in a script. The corresponding lines are

#!/bin/sh
[.........]
grepErg=`echo $datum | grep "^$1[0-2]$\|$0[1-9]$20[0-1][0-9]$"`

Hope you can help me.

Greetings,
Markus

Re: grep and |

Dennis Handly — Wed, 22 Aug 2007 04:33:52 GMT

grep doesn't take a "|", only egrep.
I recommend you not use grep -E if you can use grep -e xxx -e yyy.
But since you are using tricky "()", you need -E.
I got your query to work with this pattern:
grep -E "^(1[0-2])|(0[1-9])20[0-1][0-9]$"

Re: grep and |

Markus Pöstinger — Wed, 22 Aug 2007 04:41:13 GMT

Thank you very much. :)