Bash
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Contents
Environment
Put this in front of any script to avoid problems when running the script in other languages! The en_US locale should be avaiabel on all systems:
export LC_MESSAGES="en_US.UTF-8" export LC_TYPE="en_US.UTF-8" export LANGUAGE="en_US.UTF-8
Terminal or GUI
You can determine, if a script is running in a terminal (TTY) or within a gui:
# check, if we are running in a terminal
if tset -q | grep linux
then
echo "Running in terminal session ... continue the script "
GUI=0
else
# Open a GUI dialog
if zenity --question --title "GUI Dialog" \
--text "Would you like to continue?"
then
# set some vars
GUI=1
else
exit 1
fi
fi
Sending mails
mailx - former known as nail
Tested in
- Ubuntu 12.04
- Ubuntu 14.04
Tested with:
- gmx
Inspired by
Install packages
sudo apt-get install ca-certificates heirloom-mailx msmtp
Edit configuration files
One for msmtp:
vim ~/.msmtprc
# config options: http://msmtp.sourceforge.net/doc/msmtp.html#A-user-configuration-file defaults logfile /tmp/msmtp.log # settings for gmx account gmx auth on host mail.gmx.de port 587 user username@gmx.de from username@gmx.de password PASSHERE tls on tls_trust_file /etc/ssl/certs/ca-certificates.crt # settings for google account gmx auth on host smtp.gmail.com port 587 user username@gmail.com from username@gmail.com password PASSHERE tls on tls_trust_file /etc/ssl/certs/ca-certificates.crt # set default account to account default: gmx
One for mailx:
vim ~/.mailrc
# set smtp for mailx
# (default)
set from="username@gmx.de"
set sendmail="/usr/bin/msmtp"
set message-sendmail-extra-arguments="-a gmx"
account gmx {
set from="username@gmx.de (Your name) send from command line"
set sendmail="/usr/bin/msmtp"
set message-sendmail-extra-arguments="-a gmx"
}
account google {
set from="username@gmail.com (Your Name) send from command line"
set sendmail="/usr/bin/msmtp"
set message-sendmail-extra-arguments="-a google"
}
Send the mail
mailx -A gmx -s "gmx test" username@gmx.de < /tmp/test_email.txt echo "mail text" | mailx -A gmx -s "gmx test" username@gmx.de cat /tmp/test_email.txt | mailx -A gmx -s "gmx test" username@gmx.de
Sending an attachment
echo "mail text" | mailx -A gmx -a attachment.file -s "gmx test" username@gmx.de
Sending dmesg message (or other) via pipe
dmesg | mailx -A gmx -s "$HOSTNAME dmesg" username@gmx.de
Explanation:
-A xxx : the name of the isp account that must match in ~/.msmtprc AND .mailrc.
If not specified, the as default defined account will be used.
-s "Text" : the subject
-a Datei : Attachment
Singleton
The singleton pattern is a very handy one. You can realise it in bash like this:
if ps x | grep -v grep | grep -v $$ | grep $0 | grep -v subl | grep -v vi
then
echo "$0 already running. Exiting"
exit 1
else
################################################
# PUT YOUR CODE HERE
# vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
./run_me
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
################################################
fi
Grep
Grep a steam with tail, head
Sometimes you need not to filter a standard out only once, but with tail
tail -f -n 300 /var/log/syslog | stdbuf -o0 grep PATTERN
remove empty lines
cat some_text | egrep -v '^#|^$'
remove carriage return (newline
echo "something" | tr -d '\n'
Graphical Tools
Sometimes you need to get out of yor script, give a message to your users - visually.
notify-send
#!/bin/bash
notify_start() {
aplay Critical_Error.wav
notify-send "Backup is is mounted." \
-i /usr/share/icons/gnome/48x48/actions/document-open-recent.png \
"Read and write support for you is working."
}
notify_end() {
notify-send "Backup Drive is not ready!" \
-i /usr/share/icons/gnome/48x48/actions/stock-delete.png \
"Resolve the problem and save your work"
}
while(true); do
if touch /backup/testfile
then
rm /backup/testfile
notify_start
else
notify_end
fi
sleep 10
done
Monitoring
Sometimes you like to run a monitor in the background. Here an example for checking if a drive had an drive error.
#!/bin/bash
if ps x | grep -v grep | grep -v $$ | grep $0 | grep -v subl | grep -v vi
then
echo "$0 already running. Exiting"
exit 1
else
################################################
# PUT YOUR CODE HERE
# vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
notify_start() {
aplay /local/share/sounds/KDE_Critical_Error.wav
notify-send "Backup is is mounted." \
-i /usr/share/icons/gnome/48x48/actions/document-open-recent.png \
"Read and write support for you is working."
}
notify_end() {
aplay /local/share/sounds/KDE_Critical_Error.wav
notify-send "Backup Drive is not ready!" \
-i /usr/share/icons/gnome/48x48/actions/stock-delete.png \
"Resolve the problem and save your work"
}
while(true); do
message_head="SSD WRITE TEST:"
message_time="date +%F_%Hh:%Ms:%Nms"
error="ERROR:"
logger "${message_head} $(${message_time}) starting sync"
if sync
then
logger "${message_head} $(${message_time}) sync finished successfully."
else
logger "${message_head} $(${message_time}) ${error} while do sync."
fi
sleep 2
if touch ~/testfile
then
logger "${message_head} $(${message_time}) touched testfile in home successfully."
if rm ~/testfile
then
logger "${message_head} $(${message_time}) removed testfile in home successfully."
else
logger "${message_head} $(${message_time}) ${error} while removing tesfile in home."
fi
else
logger "${message_head} $(${message_time}) ${error} while touching tesfile in home."
notify_end
fi
sleep 28
done
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
################################################
fi
sed
Search and replace text in a document with sed
# Search and replace text in a document globally or first
# apos@gmx.de - 2008
#
# param1: search string
# param2: replace string
# param3: the document URL
search_replace_global(){
search="$(printf "%s\n" "${1}" | sed 's/[][\.*^$/]/\\&/g')"
replace="$(printf "%s\n" "${2}" | sed 's/[][\.*^$/]/\\&/g')"
sed -i "s/${search}/${replace}/g" "${3}"
}
search_replace_first(){
search="$(printf "%s\n" "${1}" | sed 's/[][\.*^$/]/\\&/g')"
replace="$(printf "%s\n" "${2}" | sed 's/[][\.*^$/]/\\&/g')"
sed -i "s/${search}/${replace}/" "${3}"
}
Cut text out of a file
# Cut text out of a file.
# Searches for the first (!) - and only the first - occurence of the Expression
# "FIRST_TEXT_FRAGMENT" and then, from that line on to the first occurence of
# "LAST_TEXT_FRAGMENT". It then cuts the lines between these two -
# including the found lines (!) - out with sed.
#
# param1: first text fragment
# param2: second text fragment
# param3: input file - the file to inspect
cut_text(){
THEDOC="${3}"
#FIRST_TEXT_FRAGMENT="$(printf "%s\n" "${1}" | sed 's/[][\.*^$/]/\\&/g')"
FIRST_TEXT_FRAGMENT="${1}"
#LAST_TEXT_FRAGMENT="$(printf "%s\n" "${2}" | sed 's/[][\.*^$/]/\\&/g')"
LAST_TEXT_FRAGMENT="${2}"
BEGIN_CUT=$(cat ${THEDOC} | fgrep -n --max-count=1 "${FIRST_TEXT_FRAGMENT}" | cut -d':' -f1)
BEGIN_CUT=$(expr ${BEGIN_CUT})
echo ${BEGIN_CUT}
END_CUT=$(cat ${THEDOC} | sed -e "1,${BEGIN_CUT}d" | fgrep -n --max-count=1 "${LAST_TEXT_FRAGMENT}" | cut -d':' -f1)
echo ${END_CUT}
END_CUT=$(expr ${END_CUT} + ${BEGIN_CUT})
echo ${END_CUT}
sed -i "${BEGIN_CUT},${END_CUT}d" "${THEDOC}"
}
Renaming files with bad content
find . -depth -name "*.*" -execdir rename 's/:/_/g;s/:/_/g;s/</_/g;s/>/_/g;' "{}" \;
also see
sudo apt-get install detox detox --help
Kill all processes with a certain name
vim ~/bin/killall_
#!/bin/bash
PROGRAM="${1}"
if [ ${PROGRAM} = "" ]
then
echo "Programname required."
exit 1
fi
KILL="$(ps x | grep -v grep | grep -v killall | grep -v $(basename $0) | grep "${PROGRAM}" | sed 's/^\ //' | cut -d' ' -f1 | sed 's/ //g')"
if [ "${KILL}" != "" ]
then
for killme in "${KILL}"
do
echo "Killing <9> process number $killme"
kill -9 $killme
done
else
echo "Nothing to kill ..."
fi