Why does inotitywait with "echo '---' >> file" only emit an "OPEN" event? - shell

Why does echo "---" >> file only generate a ./ OPEN file event? Shouldn't it generate other events too?
For example:
# In a script:
while true; do
change=$(inotifywait -q -r . )
echo $change
done
# Somewhere else:
echo "--" >> file
echo "--" >> file
echo "--" >> file

it is exiting after the first event and starting the loop over, by the time the first watch is removed and the second added, the events have already transpired. You can try:
inotifywait -q -m -r . | while read CHANGE; do
case "$CHANGE" in
*)echo $CHANGE;;
esac
done
the -m will continue monitoring after the first event

Related

Handling logs of bash script and comments in text file

I am trying to read a text file which has few commented starts with '#', my bash script should read the lines of the text file which doesn't start with '#'.
Also im trying to capture the output of echo statements in both logs and to show it console window for the user understanding.
I have tried to use the below query for capturing logs and printing in console
exec 2>&1 1>>$logfile
For reading each line of the file and calling the function, i have declared an array and to eliminate lines which starts with '#' , i have used the below query.
declare -a cmd_array
while read -r -a cmd_array | grep -vE '^(\s*$|#)'
do
"${cmd_array[#]}"
done < "$text_file"
Note : I need to eliminate the line starts with '#' and remaining lines to be read and place in array as declared.
Bash script
***********
#! /bin/bash
Function_1()
{
now=$( date '+%Y%m%d%H%M' )
eval logfile="$1"_"$now".log
exec 2>&1 1>>$logfile ### Capture echo output in log and printing in console
#exec 3>&1 1>>$logfile 2>&1
echo " "
echo "############################"
echo "Function execution Begins"
echo "############################"
echo "Log file got created with file name as $1.log"
eval number=$1
eval path=$2
echo "number= $number"
ls -lR $path >> temp.txt
if [ $? -eq 0 ]; then
echo " Above query executed."
else
echo "Query execution failed"
fi
echo "############################"
echo "Function execution Ends"
echo "############################"
echo " "
}
text_file=$1
echo $text_file
declare -a cmd_array ### declaring a array
while read -r -a cmd_array | grep -vE '^(\s*$|#)' ### Read each line in the file with doesnt starts with '#' & keep it in array
do
"${cmd_array[#]}"
done < "$text_file"
Text file
*********
####################################
#Test
#Line2
####################################
Function_1 '125' '' ''
Function_1 '123' '' ''
Consider piping the grep output into the read:
declare -a cmd_array ### declaring a array
### Read each line in the file with doesnt starts with '#' & keep it in array
grep -vE '^(\s*$|#)' < "$text_file" | while read -r -a cmd_array
do
"${cmd_array[#]}"
done
I'm not clear about the output/logging comment. If you need the output appended to a file, in addition to stdout/console), consider using the 'tee' (probably 'tee -a')
I tested with the input file inputfile
echo a
Function_1 '125' '' ''
# skip me
Function_1 '123' '' ''
echo b
and wrote this script:
declare -a cmd_array ### declaring a array
while read -r -a cmd_array
do
echo "${cmd_array[#]}"
"${cmd_array[#]}"
echo
done < <(grep -vE '^(\s*$|#)' inputfile)
For showing output in log and console, see https://unix.stackexchange.com/a/145654/57293
As #GordonDavisson suggested in a comment, you get a simular result with
source inputfile
ignoring comments and empty lines, and calling functions, so I am not sure why you would want an array. This command can be included in your master script, you do not need to modify the inputfile.
Another advantage of sourcing the input is the handling of multi-line input and # in strings:
Function_1 '123' 'this is the second parameter, the third will be on the next line' \
'third parameter for the Function_1 call'
echo "This echo continues
on the next line."
echo "Don't delete # comments in a string"
Function_1 '124' 'Parameter with #, interesting!' ''

Handling files with spaces in a bash selection menu

I am trying to make this script handle file with spaces in them. it is supposed show and execute the content of files in a directory. when I select a file with a space in it, bash fails with bash: foo: no such file or directory, What am I missing to make this handle files correctly
# /etc/skel/.bashrc
#Interactive shell detection
if [[ $- != *i* ]] ; then
# Shell is non-interactive. Be done now!
return
fi
#kv-bash (easy) var database & setup of info
echo "type 'menu' for a bash menu"
#done####################
#to easily launch crouton enviroments
addentry() {
cd ~/.sslm
echo "Name your menu entry."
read entry
sleep 1s
if [ -e "$entry " ]
then
echo "Error, Menu entry already exists"
addentry
else
echo "what do you want the entry to do?"
read entryexec
echo "$entryexec && menu"> ~/.sslm/"$entry"
echo "done"
cd ~/
fi
sleep 1s
}
###################
delentry() {
cd ~/.sslm
ls -x
echo "what entry do you want to delete?"
read del
rm "$del"
echo "the work has been done, he is dead"
}
###################
menu() {
clear
cd ~/.sslm
echo "-- simple shell launcher menu v1.o --"
# set the prompt used by select, replacing "#?"
PS3="Use number to select a file or 'exit' to leave: "
# allow the user to choose a file
select filename in *
do
# leave the loop if the user says 'stop'
if [[ "$REPLY" == exit ]]; then
cd ~/
break
fi
# complain if no file was selected, and loop to ask again
if [[ "$filename" == "" ]]
then
echo "'$REPLY' is not a valid number"
sleep 1s
continue
fi
# now we can use the selected file, trying to get it to run the shell
script
. $filename
# it'll ask for another unless we leave the loop
break
done
}
menu
also, this is on a chromebook, so there is no apt.
At this part:
script
. $filename
I just needed to change to . "$filename"
thx #PesaThe

Bash- How to check if file is empty in a loop

I need to check in Bash file is empty,
if it's empty keep tracking him until something is written to it.
In case something was written to it echo it to the screen and stop checking the file content.
for [ -s diff.txt ]; do
echo "file is empty - keep checking it "
done
echo "file is not empty "
cat diff.txt
Why not just use a while?
while ! [ -s diff.txt ]; do
echo "file is empty - keep checking it "
sleep 1 # throttle the check
done
echo "file is not empty "
cat diff.txt
The loop will run as long as ! [ -s diff.txt ] is true. If you prefer, you can use until instead of while and remove the negation (!).

define "$key" use it in a script, but also store it

How can I create a specific line in another file using bash please? Like
echo "Please input the days you want to keep "
$key= ?
touch .beebrc; keep="$key"
where the file ".beebrc" has a line 'keep= x' and "$key" is created in the main script.
But how do I define "$key" please? And write it into ".beebrc" as a new line at position/line 8? The full function is -
function trim {
echo;
read -t "$temi" -n1 -p ""$bldgrn" Do you want to delete some of your download history? [y/n/q/r] $(tput sgr0)" ynqr ;
case "$ynqr" in
[Yy]) echo
read -t "$temi" -n3 -p ""$bldgrn" Please input the days you want to keep $(tput sgr0)" key ## ask
if test -e .beebrc && grep -q "^keep=" .beebrc 2>/dev/null ; then
sed -i "s/^keep=.*/keep=$key/" .beebrc
else
echo "keep=$key" >> .beebrc
#fi
cd /home/$USER/.get_iplayer
eval "$player" --trim-history "$key"; cd; ques;
#echo;;
[Nn]) ques;;
[Qq]) endex;;
[Rr]) exec "$beeb";;
* ) echo ""$bldgrn" Thank you $(tput sgr0)";;
esac
fi
};
Does this help in defining it all? (Sorry, should've put it in at first)
Perhaps:
read -p "Please input the days you want to keep: " key ## Ask.
echo "keep=\"$key\"" > .beebrc ## Store.
Use read to capture user input into a variable, and then write it to your file.
For example:
echo "Please input the days you want to keep "
read key
echo $key > .beebrc
#!/bin/bash
read -p "Please input the days you want to keep: " key
if test -e .beebrc && grep -q "^keep=" .beebrc 2>/dev/null ; then
sed -i "s/^keep=.*/keep=$key/" .beebrc
else
echo "keep=$key" >> .beebrc
fi
This script:
Prompts for input and stores the value in $key
Tests if .beebrc exists and that a line beginning "keep=" exists in it. If so, replace the keep= line with keep=$key
Otherwise append a new line/create the file with keep=$key.
This will need validation added because user input should not be trusted. (this answer might help)

multiple sed operations creating empty file

When as part of shell script only one line is operating on a file using sed command the redirected file contains the updated data, as below
cat ${PROP_PATH}/${PROP_FILE} | sed "s!${ISTR_KEY}=.*!${ISTR_KEY}=${SIM_ISTR_KEY_VAL}!" > ${UPDATEDPROPS_DIR}/${PROP_FILE}
whereas when it is executed as part of a shell script, where after this another sed command updates the same file as in the below script at the end what i get is an empty file, why ? ..... ideas please.
(check 'switchAll2Sim()' function below)
#!/bin/ksh
#
SIM_ICR_KEY_VAL="http://www.example.com/sim/http/icr"
SIM_ISTR_KEY_VAL="http://www.example.com/sim/http/istr"
SIM_GT_KEY_VAL="http://www.example.com/sim/http/gtr"
#
ICR_KEY="interface.url.icr"
ISTR_KEY="interface.url.istr"
GT_KEY="interface.ws.url.gt"
## Property Files
PROP_PATH=""
PROP_FILE="properties"
##
DATE=`date +%m%d%Y`
DATETIME=`date +%m%d%Y-%T`
BCKUP_DIR=_bckup
UPDATEDPROPS_DIR=_updatedprops
# ----------------------------------
pause(){
echo "Press [Enter] key to continue..."
read fackEnterKey
}
permissions(){
chmod 777 ${UPDATEDPROPS_DIR}
}
backup(){
if [ ! -d "${BCKUP_DIR}" ]; then
mkdir ${BCKUP_DIR}
fi
if [ ! -d "${UPDATEDPROPS_DIR}" ]; then
mkdir ${UPDATEDPROPS_DIR}
fi
permissions
## keep backup of properties
cp ${PROP_PATH}/${PROP_FILE} ${BCKUP_DIR}/${PROP_FILE}_${DATETIME}
echo "Backup of property files completed at: " ${DATETIME}
}
#-------------------------------------------------------------
# switch all properties to SIM
#-------------------------------------------------------------
switchAll2Sim(){
backup
#
# update files
cat ${PROP_PATH}/${PROP_FILE} | sed "s!${ISTR_KEY}=.*!${ISTR_KEY}=${SIM_ISTR_KEY_VAL}!" > ${UPDATEDPROPS_DIR}/${PROP_FILE}
cat ${UPDATEDPROPS_DIR}/${PROP_FILE} | sed "s!${ICR_KEY}=.*!${ICR_KEY}=${SIM_ICR_KEY_VAL}!" > ${UPDATEDPROPS_DIR}/${PROP_FILE}
cat ${UPDATEDPROPS_DIR}/${PROP_FILE} | sed "s!${GT_KEY}=.*!${GT_KEY}=${SIM_GT_KEY_VAL}!" > ${UPDATEDPROPS_DIR}/${PROP_FILE}
echo "Switch all to SIM completed at: " ${DATETIME}
pause
}
# switch all properties to real
#-------------------------------------------------------------
switchAll2Real(){
pause
}
#-------------------------------------------------------------
dispCurrentStats(){
echo "Displaying current properties..."
echo "*********************************"
echo " File: " ${PROP_PATH}/${PROP_FILE}
grep ${ICR_KEY} ${PROP_PATH}/${PROP_FILE}
grep ${ISTR_KEY} ${PROP_PATH}/${PROP_FILE}
grep ${GT_KEY} ${PROP_PATH}/${PROP_FILE}
#
echo "*********************************"
pause
}
show_menus() {
clear
echo "~~~~~~~~~~~~~~~~~~~~~"
echo " M E N U"
echo "~~~~~~~~~~~~~~~~~~~~~"
echo "1. Display current properties"
echo "2. Switch all to real"
echo "3. Switch all to simulator"
echo "4. Exit"
}
# read input from the keyboard and take a action
read_options(){
read option
case $option in
1) dispCurrentStats ;;
2) switchAll2Real ;;
3) switchAll2Sim ;;
4) exit 0;;
*) echo "Please insert options 1 ~ 4";;
esac
}
# -----------------------------------
# Main - infinite loop
# ------------------------------------
while true
do
show_menus
read_options
done
Thanks, using '-i, says [sed: illegal option -- i]
Then you have to work with tmp files.
cp foo foo.tmp
sed "s/x/y/" foo.tmp > foo
/bin/rm foo.tmp
OR
sed "s/x/y/" foo > foo.tmp
/bin/mv -f foo.tmp foo
is probably more efficient.
I hope this helps.
Your problem is that cat is reading from the same file that sed is writing to.
cat foo | sed "s/x/y/" > foo
Will not work because cat and sed run at the same time, not one after the other.
To fix this try the -i option to sed.
sed -i "s/x/y/" foo

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