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--- useful:linux-commands [2022/08/25 15:46] – admin
+++ useful:linux-commands [2025/09/23 07:58] (current) – admin
@@ Line 2: / Line 2: @@
 ====== Linux Commands ======
+===== Removing comments from config files =====
+from 20-lmtp.conf as an example:
+     grep '^[[:blank:]]*[^[:blank:]#;]' 20-lmtp.conf
+===== Installing a GPG key =====
+Example:
+     wget -O- https://download.webmin.com/jcameron-key.asc | sudo gpg --dearmor | sudo tee /usr/share/keyrings/jcameron-key.gpg > /dev/null 2>&1
+Then need to edit the sources.list file to look something like:
+     deb [signed-by=/usr/share/keyrings/jcameron-key.gpg] https://download.webmin.com/download/repository sarge contrib
 ===== Change permissions for whole directory structure =====
@@ Line 17: / Line 33: @@
 ===== Delete all files with given pattern =====
-Adapt as required
+     find . -name '*altauserpoints*' -print0 | xargs -0 -P0 rm
+Adapt as required.
+===== Make a change in every file in a directory  =====
+     sed -i 's/foo/bar/g' *
+To make the change through a whole directory tree:
+     find ~/public_html/my_website/pages -type f -exec sed -i 's/2017/2018/g' {} \;
+===== Search within specific file type =====
+     grep -ir removed --include="*.txt" .
+will search files with extension .txt ignoring case (-i)
+===== Bluetooth =====
+Using this from the command line seems to do more than the GUI:
+     bluetoothctl
+===== Limiting journal log size =====
+Edit the file:
+     /etc/systemd/journald.conf
+and set SystemMaxUse, for example
+     SystemMaxUse=250M
+Then restart journal with:
-     ind . -name '*altauserpoints*' -print0 | xargs -0 -P0 rm
+     systemctl restart systemd-journald