Differences

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--- bash_oneliners [2015/10/08 13:28] – admin
+++ bash_oneliners [2025/08/06 12:07] (current) – admin
@@ Line 2: / Line 2: @@
-  * Remove offending key from known_hosts file with one command
+  * Whats my WAN IP?
 <code>
-$ sed -i 18d .ssh/known_hosts
+dig +short myip.opendns.com @resolver1.opendns.com
 </code>
-  * Whats my WAN IP?
+  * Find large files, print 10 largest files in dir
 <code>
-$ dig +short myip.opendns.com @resolver1.opendns.com
+find . -printf '%s %p\n'|sort -nr|head
 </code>
-  * Math on the cli
+  * size of all files older than mtime
 <code>
+find . -mtime +7 -print0 | du -hc --files0-from - | tail -n 1
+</code>
+  * To find the largest file in all sub-directories:
+<code>
+find . -type f -exec ls -s {} \; | sort -nr | awk 'NR==1 { $1=""; sub(/^ /, ""); print }'
+</code>
+  * grep for valid IP Addresses.
+<code>
+grep -E -o "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)" file.txt
+</code>
+  * show used inode count for subdirectories.
+<code>
+find */ | sed 's!/.*!!' | uniq -c
+</code>
+  * free all caches
+<code>
+free && sync && echo 3 > /proc/sys/vm/drop_caches && free
+</code>
+  * rescan all SCSI buses
+<code>
+for i in /sys/class/scsi_host/host{0..32}/scan; do echo "- - -" > $i; done
+</code>
+  * enlarge LVM
+<code>
+fdisk /dev/sdk
+#set partition type to Linux LVM (type 8e)
+pvcreate /dev/sdk1
+vgextend VolGroupDB /dev/sdk1
+lvextend -l +100%FREE /dev/mapper/VolGroupDB-data
+resize2fs -p /dev/mapper/VolGroupDB-data
+#for xfs use xfs_growfs /dev/mapper/VolGroupDB-data
+parted -a optimal /dev/sdc mklabel gpt
+parted -a optimal /dev/sdc mkpart p 0% 100%
+parted -a optimal /dev/sdc set 1 lvm on
+vgextend VGEXL /dev/sdf1
+lvresize -l +100%free /dev/mapper/VGEXL-exllv
+</code>
+  * Enlarge LVM 2
+<code>
+echo '1' > /sys/class/scsi_disk/0\:0\:3\:0/device/rescan
+yum install cloud-utils-growpart
+growpart  /dev/sdd 1
+pvresize /dev/sdd1
+lvextend -l +100%FREE /dev/mapper/VGKUB-lv_kub
+xfs_growfs /dev/mapper/VGKUB-lv_kub
+</code>
-Basic operations
+  * polkit logging for debugging
+<code>
-$ echo $((1+1))
+cat /etc/polkit-1/rules.d/50-apt.rules
-$ echo $((3-1))
-$ echo $((4/2))
-$ echo $((1*2))
-Basic ops using expr
+polkit.addRule(function(action, subject) {
+    polkit.log("Evaluating action: " + action.id);
+    polkit.log("User: " + subject.user + ", Groups: " + subject.getGroups());
-$ expr 60 / 5
+    if (action.id.startsWith("org.freedesktop.packagekit.") ||
+        action.id == "org.debian.apt.update-cache" ||
+        action.id == "org.debian.apt.upgrade" ||
+        action.id == "org.debian.apt.remove" ||
+        action.id == "org.debian.apt.upgrade-packages" ||
+        action.id == "org.debian.apt.install") {
+        polkit.log("Authorization granted for action: " + action.id);
+        return polkit.Result.YES;
+    }
-Floating point calculations
+    polkit.log("Authorization denied for action: " + action.id);
+});
-$ echo "2*2.2/2.2" | bc
-$ echo "4.4+7/8-(4.74*3.14)" | bc
--10.48
-using here-doc
-$ bc <<< "4.4+7/8-(4.74*3.14)"
--10.48
-a bash funtion, for your .bashrc
-calc () {
-    bc -l <<< "$@"
-}
-usage:
-$ calc 65320*670
-43764400
 </code>