Bash script - if and else if statements

Question

I am quite new to bash scripts so take it easy on me;).

I have a file which does some checks before initiating a /warner file which sends an email.

No what the script should do is:

If the word 'rror' is to be found in the log file and if the file is younger then 24 hours > send failed email

If the file is older than 24 hours > send not running error

If none of the above are true and the file is less than 24 hours old and if it contains word 'uccess' > send successful email.

Script it self

string=rror
string1=ucces

FILE=/var/log/rsnapshot.log
OLDTIME=86400
CURTIME=$(date +%s)
FILETIME=$(stat $FILE -c %Y)
TIMEDIFF=$(expr $CURTIME - $FILETIME)

#tail -n0 -F /var/log/rsnapshot.log | \

while read LINE
do
  if [ echo "$LINE" | grep "$string" 1>/dev/null 2>&1 -a $TIMEDIFF -lt $OLDTIME ]; // <- line 18
    then
        /etc/init.d/warner "Warning from Socrates Backup" "Backup Failed"
  elif [ $TIMEDIFF -gt $OLDTIME ];
    then
        /etc/init.d/warner "Warning from Socrates Backup - Backup Not Running!" "Backup file not running"
  elif echo "$LINE" | grep "$string1" 1>/dev/null 2>&1
    then
        /etc/init.d/warner "Message from Socrates" "Backup Sucessfully Completed"
  fi
done </var/log/rsnapshot.log

At present time it does send me a successfull email (because the file is less than 24hours and it does have a 'uccess' message. However are these if / elseif written correctly ? if anything should fail will they get triggered ? and also i am getting this error

line 18: [: missing `]'

Where is line 18? If I count the lines you pasted, it is in then. — fedorqui
– fedorqui, Commented Dec 4, 2015 at 14:09
@fedorqui Apologies did not see your comment. The 18th line is the first if — Maciej Cygan
– Maciej Cygan, Commented Dec 4, 2015 at 15:12

Dummy00001 · Accepted Answer · 2015-12-04 14:15:04Z

6

This line is completely wrong:

if [ echo "$LINE" | grep "$string" 1>/dev/null 2>&1 -a $TIMEDIFF -lt $OLDTIME ];

What you mean probably is:

if echo "$LINE" | grep -q "$string" && [ $TIMEDIFF -lt $OLDTIME ];

You want to read Compound Commands from the man bash, while keeping in mind that [ is just a command too. (Try help test.)

answered Dec 4, 2015 at 14:15

Dummy00001

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2 Comments

Maciej Cygan Over a year ago

Yup thats the one. i have to do more RTFM

Dummy00001 Over a year ago

@MaciejCygan, In the beginning, the internal bash's help command was extremely useful to me. The man bash is just too huge to swallow, while for basic syntax the help <cmd> + googling is more than sufficient.

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