Shell Programming and Scripting

here is my script
########
#! /bin/sh
export PATH=$PATH:/opt/mysql/bin/
#echo $PATH
echo $LD_LIBRARY_PATH
USER="root"
PASS="xyz"
DB="sme"
DATE=$(date +%d%b%y_%k.%M.%S)
#DATE=`date +%y-%d-%m`
if
mysqldump -u $USER -p$PASS $DB | gzip -9>/home/backup1/today_sme-$DATE.sql.gz
then
find /home/backup1 -mtime +0 -exec rm -f {} \;
echo "done"
else
echo "not done"
fi
########

I want If mysqldump -u $USER -p$PASS $DB | gzip -9>/home/backup1/today_sme-$DATE.sql.gz
executes successfully then only
find /home/backup1 -mtime +0 -exec rm -f {} \;
execute
else echo "not done" execute

Actually this is a pipeline consisting of two components (mysqldump and gzip). The success of this pipeline depends in the success of the two programs; either mysqldump may fail or gzip (or both ofcourse). It's better to rewrite these lines as follows:

Code:

set -o pipefail
mysqldump -u $USER -p$PASS $DB | gzip -9>/home/backup1/today_sme-$DATE.sql.gz
if [ $? -ne 0 ]; then
    blabla
else
    blabla
fi

The pipefail bash option is controlling the exit status of a pipeline (read the manual pages for bash). Of course the two components must be written correctly from their authors (exiting with non zero exit statuses when failures occur).

I changes my script as follow

############################################################
#! /bin/sh
export PATH=$PATH:/opt/mysql/bin/
#echo $PATH
echo $LD_LIBRARY_PATH
USER="root"
PASS="XYZ"
DB="sme"
DATE=$(date +%d%b%y_%k.%M.%S)
#DATE=`date +%y-%d-%m'
set -o pipefail
mysqldump -u $USER -p$PASS $DB | gzip -9>/home/backup1/today_sme-$DATE.sql.gz;
if[$? -ne 0]; then
find /home/backup1/ -mtime +4 -exec rm -f {} \;
exit 0
else
echo "done"
exit 1
fi

#############################################################

but while executing it shows error

bck_script.sh: line 19: syntax error near unexpected token `then'
bck_script.sh: line 19: `if[$? -ne 0]; then '

You must use spaces in brackets:

if [ $? -ne 0 ]; then

Thanks

Leave a space after between if and bracket too!

if [ $? -ne 0 ]; then

I changes

set -o pipefail
ysqldump -u $USER -p$PASS $DB | gzip -9>/home/backup1/today_sme-$DATE.sql.gz;
if [ $? -ne 0 ]; then
echo "done"
find /home/backup1/ -mtime +4 -exec rm -f {} \;
exit 0
else
echo "not done"
exit 1
fi

still it executes done while mysqldump(which changes to sqldump for test purpose) not executing