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advanced-bash-techniques
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advanced-bash-techniques
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.. _advanced-bash-techniques-1:

advanced bash techniques
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find and change all files

.. code-block:: bash

sudo find . -type f -print0 \| xargs -0 ls -hal

sudo find . -type f -print0 \| xargs -0 sudo chown www-data:www-data

sudo find . -type f -print0 \| xargs -0 sudo chmod 0644

find and change all directories:

sudo find . -type d -print0 \| xargs -0 sudo chmod 0775

Remove a particular line from all files in a directory
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.. code-block:: bash

for file in /tmp/test/\* do cp -p $file $file.tmp egrep -v
“RegexToRemove” $file.tmp > $file rm -rf $file.tmp done

apache logs count unique ip addresses
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.. code-block:: bash

sudo cat access.log \| awk ‘{ print $1; }’ \| sort \| uniq -c \| sort -n

Bash Perl search and replace multiple files one liner
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.. code-block:: perl

perl -pi -w -e ‘s/search/replace/g;’ \*.extension

explanation:

**-e** means execute the following line of code.

**-i** means edit in-place

**-w** write warnings

**-p** loop

Bash sed search and replace multiple files one liner
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.. code-block:: sed

sed -i’’ -e ‘s/search/replace/g’ \*

Get a coma separated list of libvirt guests
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.. code-block:: bash

virsh list \| egrep -v ‘Domain|Name\|—-\|^$’ \| awk ‘{printf “%s,” ,
$2}’ > /tmp/virthosts