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--- wiki:bash_commands [2022/09/19 23:53] – created antisa
+++ wiki:bash_commands [2023/08/07 10:30] (current) – add Remove old unused kernels antisa
@@ Line 2: / Line 2: @@
 ====== Bash commands ======
-Remove first character:
+===== Remove first character: =====
   for f in *; do mv "$f" "${f:1}"; done
-Add 8 to filename:
+==== Add 8 to filename: ====
   for f in *; do mv "$f" "8$f"; done
+==== Sort folders by disk usage, larger first: ====
+  du -sh /* | sort -hr
+==== Checksum directory recursively ====
+  find /var/lib/mysql -type f -print0 | xargs -0 sha256sum > mysql.sha256sum
+==== Comment and uncomment lines containing specific strings ====
+  sed -e '/multiverse/s/^/#/' -i /etc/apt/sources.list
+  sed -e '/multiverse/s/^#//' -i /etc/apt/sources.list
+==== Search and replace strings in multiple html files: ====
+  for file in $(grep -cr --include "*.html" "somestring" . | awk -F ":" '{print $1}');do sed -i 's/\bsomestring\b/newstring/g' $file;done
+\b is word boundary, meaning it won't select strings like string_somestring_smth_smth Put sed -n... and ..newstring/gp' to just see the changes without actually making them.
+==== Print from certain line to certain line: ====
+  zcat server_20170726-060002.log.gz | awk '/2017-07-25\ 20:54:59.381/,/2017-07-25\ 21:16:00.948/' - > incident.txt
+==== Sed add word/string after specific string on same line i.e. add "blablah" after " localhost ": ====
+  sed 's/\blocalhost\b/& blablah/' file
+==== Print disk usage, summarize in GB ====
+   du -s /var/lib/mysql/mydb/{table1,table2,table3}.* | awk '{ sum+=$1} END {printf sum/1024^2; print " GB"}'
+==== Remove old unused kernels ====
+  sudo dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'|grep -E "(image|headers|modules)" | grep -v hwe | xargs sudo apt-get -y purge
 ====== Tested on ======
   *