submit_passive_check.sh – Contains functions to easily submit passive Nagios checks. Very useful for servers that cannot run the NRPE agent. The only external requirements are curl, awk, and grep which are installed by default on the majority of Linux based distros (ie: CheckPoint Gaia, F5, etc). A simple example of checking the current CPU load […]
Read More →Simple example of parsing the command line in a bash script:
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#!/bin/bash EXTRA_ARGS=() VERBOSE=0 # Set default value for the verbose flag while [[ $# -gt 0 ]]; do case $1 in -h|--host) HOST="$2" shift shift ;; -u|--username) USER="$2" shift shift ;; -v|--verbose) VERBOSE=1 shift ;; --help) echo "$(basename $0) [-h|--host <hostname>] [-u|--user <username>] [-v|--verbose] [arg1] [arg2] [...]" exit 1 ;; *) EXTRA_ARGS+=("$1") shift ;; esac done echo "HOST = ${HOST}" echo "USER = ${USER}" echo "VERBOSE = ${VERBOSE}" if [[ -n $EXTRA_ARGS ]]; then i=0 for thisarg in ${EXTRA_ARGS[*]}; do (( i++ )) echo "EXTRA${i} = ${thisarg}" done fi |
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Toss this in your ~/.bashrc to use the Gnome Yelp help viewer to open a man page. This replaces the man command with a function and only uses the CLI version of man if there’s no running X session.
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#!/bin/bash man() { if [[ $(xhost) ]]; then { yelp "man:$@" & } >/dev/null 2>&1 ; disown else /usr/bin/man "$@" fi } |
If an X session is running it instead opens the man page in Yelp as […]
Read More →This function will trim leading and trailing tab and space characters from a string:
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trim() { printf "$*" | awk '{ gsub(/^[ \t]+|[ \t]+$/, ""); print }' } |
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This addresses issues displaying box/line drawing characters in PuTTY. In your PuTTY session settings go to Window -> Translation. Change the Remote character set to UTF-8. On your linux box open ~/.bash_profile with your favorite editor. At the bottom add “export NCURSES_NO_UTF8_ACS=1” without quotes. Save and exit. For the change to take place in your […]
Read More →In this example I shrink the /home volume and create a new volume for /opt. Be sure to backup your data!! If you resize the volume you’re shrinking to less than the amount of data you have on it data WILL be destroyed!
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# List all logical volumes and make note of the VG Name (volume group) # and LV Name (logical volume). Also make sure you remember the original # size for the logical volume you are shrinking so you know how big to make # the new logical volume. lvdisplay –m # Stop any processes/services that may use both /opt and /home # Rename /opt and create an empty /opt directory to mount to mv /opt /opt.old mkdir /opt # Unmount /home to shrink the volume umount /home # We’re required to do a fs check before a resize operation e2fsck -f /dev/mapper/<VGname>-<LVname> # Resize the volume /home from 300G to 200G (freeing up 100G) resize2fs /dev/mapper/<VGname>-<LVname> 200G # Resize the logical volume to 200G lvreduce -L 200G /dev/mapper/<VGname>-<LVname> # Check the fs again and remount /home e2fsck -f /dev/mapper/<VGname>-<LVname> mount /home # Create a new logical volume called 'opt' in the <VGname> volume group lvcreate -L 100G -n opt <VGname> # Format the new volume with ext4 mkfs -t ext4 /dev/mapper/opt # Mount the new /opt volume mount –t /dev/mapper/<VGname>-opt /opt # Move the data from the /opt.old directory to the new /opt volume mv /opt.old/* /opt # Make sure the /opt.old directory is empty then delete it ls –l /opt.old rmdir /opt.old # Add to /etc/fstab so it mounts after a reboot /dev/mapper/<VGname>-opt /opt ext4 defaults 1 2 # Restart any processes/services you stopped earlier, or reboot now. |
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Directory Purpose / Root directory of the entire file system hierarchy /bin Essential command binaries (all users) /boot Boot loader files. /dev Device Files /etc Host specific system wide configuration files /home Users home directories /lib Libraries essential for /bin and /sbin /media Mount points for removable media /mnt Temporary mounted file systems /opt Optional […]
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dmidecode -t <type> dmidecode -t <keyword> |
DMI Keywords keyword types included bios 0, 13 system 1, 12, 15, 23, 32 baseboard 2, 10 chassis 3 processor 4 memory 5, 6, 16, 17 cache 7 connector 8 slot 9 DMI Types 0 BIOS 1 System 2 Base Board 3 Chassis 4 Processor 5 Memory Controller 6 Memory Module 7 […]
Read More →Syntax:
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date +FORMAT date +"%FORMAT" date +"%FORMAT%FORMAT" date +"%FORMAT-%FORMAT" |
How do I save time/date format to a variable?
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NOW=$(date +"%m-%d-%Y") |
%FORMAT String Description %% a literal % %a locale’s abbreviated weekday name (e.g., Sun) %A locale’s full weekday name (e.g., Sunday) %b locale’s abbreviated month name (e.g., Jan) %B locale’s full month name (e.g., January) %c locale’s date and […]
Read More →[user] is only valid in the global crontab. It is not an option for individual user crontabs. Day of week: Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sunday 0 1 2 3 4 5 6 7 Format + Examples: Min Hour Day of Month Month Day of Week [user] Command #comment 02 14 * […]
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