I'm using cat to append some results in a file but the file its empty after the execution
start="$(date +'%s%3N')"
sleep 1
echo $par
end="$(date +'%s%3N')"
duration=$(($end-$start))
cat "$par $duration" >> result.dat
echo "$par $duration" >> result.dat
You use cat which will echo the content of the file with the name formed by "$par $duration". This will most likely not exist, so that you end up appending nothing to result.dat.
Related
I am trying to read a text file which has few commented starts with '#', my bash script should read the lines of the text file which doesn't start with '#'.
Also im trying to capture the output of echo statements in both logs and to show it console window for the user understanding.
I have tried to use the below query for capturing logs and printing in console
exec 2>&1 1>>$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!' ''
title: bash parameter expansion within a scalar variable
I have a bash script which runs a diff between two files.
If there is a diff, I want it to print statement1 and statement2
They are long so i put them into variables, but the echo statement
will not expand the parameter.
Can this be done in bash?
#!/bin/bash
set -x
source="/home/casper"
target="data/scripts"
statement1="There is a change in ${i}, please check the file"
statement2="or cp /home/casper/${i} /data/scripts/$i"
for i in file1 file2l file3 file4 file5 ; do
sleep 1 ;
if diff $source/$i $target/$i 2>&1 > /dev/null ; then
echo " "
else
echo "$statement1 "
echo "$statement2 "
fi
done
exit 0
The script seems to work - it finds a diff when it needs to find one.
However this is what it prints out.
There is a change in , please check the file
or cp /home/casper/ data/scripts/
I want it to say
There is a change in file2, please check the file
or cp /home/casper/file2 /data/scripts/file2
The problem is that $i is expanded when you define statement1 and statement2, not when you expand them. Use a shell function to output the text.
notification () {
echo "There is a change in $1, please check the file"
echo "or cp /home/casper/$1 /data/scripts/$1"
}
source="/home/casper"
target="data/scripts"
for i in file1 file2l file3 file4 file5 ; do
sleep 1 ;
if diff "$source/$i" "$target/$i" 2>&1 > /dev/null ; then
echo " "
else
notification "$i"
fi
done
exit 0
This can be done using eval:
TEMPLATE_MSG="aaa \${VALUE} ccc"
...
VALUE="bbb"
eval echo "${TEMPLATE_MSG}"
But I don't recommend it, because eval is evil :-) Other option is using pattern substitution:
TEMPLATE_MSG="aaa #1# ccc"
...
VALUE="bbb"
echo "${TEMPLATE_MSG/#1#/${VALUE}}"
So you put some unique pattern in your message (e.g. #1#) and then, when you print the message, you replace it with the content of variable.
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 $option in
1) dispCurrentStats ;;
2) switchAll2Real ;;
3) switchAll2Sim ;;
4) exit 0;;
*) echo "Please insert options 1 ~ 4";;
esac
}
# -----------------------------------
# Main - infinite loop
# ------------------------------------
while true
do
show_menus
read_options
done
Thanks, using '-i, says [sed: illegal option -- i]
Then you have to work with tmp files.
cp foo foo.tmp
sed "s/x/y/" foo.tmp > foo
/bin/rm foo.tmp
OR
sed "s/x/y/" foo > foo.tmp
/bin/mv -f foo.tmp foo
is probably more efficient.
I hope this helps.
Your problem is that cat is reading from the same file that sed is writing to.
cat foo | sed "s/x/y/" > foo
Will not work because cat and sed run at the same time, not one after the other.
To fix this try the -i option to sed.
sed -i "s/x/y/" foo
I have a script that prints in a loop. I want the loop to print differently the first time from all other times (i.e., it should print differently if anything has been printed at all). I am thinking a simple way would be to check whether anything has been printed yet (i.e., stdout has been written to). Is there any way to determine that?
I know I could also write to a variable and test whether it's empty, but I'd like to avoid a variable if I can.
I think that will do what you need. If you echo something between # THE SCRIPT ITSELF and # END, THE FOLLOWING DATA HAS BEEN WRITTEN TO STDOUT will be printed STDOUT HAS NOT BEEN TOUCHED else...
#!/bin/bash
readonly TMP=$(mktemp /tmp/test_XXXXXX)
exec 3<> "$TMP" # open tmp file as fd 3
exec 4>&1 # save current value of stdout as fd 4
exec >&3 # redirect stdout to fd 3 (tmp file)
# THE SCRIPT ITSELF
echo Hello World
# END
exec >&4 # restore save stdout
exec 3>&- # close tmp file
TMP_SIZE=$(stat -f %z "$TMP")
if [ $TMP_SIZE -gt 0 ]; then
echo "THE FOLLOWING DATA HAS BEEN WRITTEN TO STDOUT"
echo
cat "$TMP"
else
echo "STDOUT HAS NOT BEEN TOUCHED"
fi
rm "$TMP"
So, output of the script as is:
THE FOLLOWING DATA HAS BEEN WRITTEN TO STDOUT
Hello World
and if you remove the echo Hello World line:
STDOUT HAS NOT BEEN TOUCHED
And if you really want to test that while running the script itself, you can do that, too :-)
#!/bin/bash
#FIRST ELSE
function echo_fl() {
TMP_SIZE=$(stat -f %z "$TMP")
if [ $TMP_SIZE -gt 0 ]; then
echo $2
else
echo $1
fi
}
TMP=$(mktemp /tmp/test_XXXXXX)
exec 3 "$TMP" # open tmp file as fd 3
exec 4>&1 # save current value of stdout as fd 4
exec >&3 # redirect stdout to fd 3 (tmp file)
# THE SCRIPT ITSELF
for f in fst snd trd; do
echo_fl "$(echo $f | tr a-z A-Z)" "$f"
done
# END
exec >&4 # restore save stdout
exec 3>&- # close tmp file
TMP_SIZE=$(stat -f %z "$TMP")
if [ $TMP_SIZE -gt 0 ]; then
echo "THE FOLLOWING DATA HAS BEEN WRITTEN TO STDOUT"
echo
cat "$TMP"
else
echo "STDOUT HAS NOT BEEN TOUCHED"
fi
rm "$TMP"
output is:
THE FOLLOWING DATA HAS BEEN WRITTEN TO STDOUT
FST
snd
trd
as you can see: Only the first line (FST) has caps on. That's what the echo_fl function does for you: If it's the first line of output, if echoes the first argument, if it's not it echoes the second argument :-)
It's hard to tell what you are trying to do here, but if your script is printing to stdout, you could simply pipe it to perl:
yourcommand | perl -pe 'if ($. == 1) { print "First line is: $_" }'
It all depends on what kind of changes you are attempting to do.
You cannot use the -f option with %z. The line TMP_SIZE=$(stat -f %z "$TMP") produces a long string that fails the test in if [ $TMP_SIZE -gt 0 ].
I am working on a bash script that needs to take a single line and add it to the end of a file if it exists, and if it does not exist create the file with the line.
I have so far:
if [ ! -e /path/to/file ]; then
echo $some_line > /path/to/file
else
???
fi
How do I perform the operation that should go in the else (adding the line of text to the existing file)?
Use two angles: echo $some_line >> /path/to/file
> creates the file if it doesn't exist; if it exists, overwrites it.
>> creates the file if it doesn't exist; if it exists, appends to it.
if [ ! -e /path/to/file ]; then
echo $some_line > /path/to/file
else
echo $some_line >> /path/to/file
fi