bash if statment unexpected behavior in crontab job
Here is the script
bash --version | head -n1
if [ "$1" == "now" ]
then
echo if now
execut job
else
echo else "_"$1"_" # make sure we are not picking any spaces
if [ condition ]
then
execut something else
fi
fi
./script now
if now
works as expected if run from interactive shell. However if invoked from cron as, the if goes to the else block instead
* * * * * root /home/user/./script now >> /tmp/log
cat /tmp/log
GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu)
else _now_
Same with "-eq" as well.
Am I missing something dead simple because I did not have breakfast yet ?
running Ubunt 14.04LTS.
Solution 1:
because the syntax is only with one equal: [ $a = $b ]
if [ ! $a = $b ]; then #with space in condition and need instruction between then and fi, else doesn't works
...Script to execute...
elif [ ! $a = $c ]; then
...Script to execute...
else
...Script to execute...
fi
conditional sh list
[ $a = $b ] && return 1 || return 0 conditionnal alternative format
if [ $a = $b -o $b = $c ] -o mean OR
if [ $a = $b -a $b = $c ] -a mean AND
if [ $a = $b -o $b = $c ] || [ $a = $b -a $a = $c ] multiple conditionnal or
if [ $a = $b -o $b = $c ] && [ $a = $b -a $a = $c ] multiple conditionnal and
if [ -z $a ] is empty or null
if [ ! -z $a ] not equal to ""
if [ -n $a ] is not empty or null
if [ $a -eq $b ] equal (numeric)
if [ $a -ne $b ] not equal (numeric)
if [ $a -gt $b ] greater than (numeric)
if [ $a -ge $b ] greater or equal than (numeric)
if [ $a -lt $b ] lower than (numeric)
if [ $a -le $b ] lower or equal than (numeric)
if [ -d $a ] is a directory
if [ -e $a ] file exist
if [ -f $a ] is a file
if [ -g $a ] is group allowed for the file
if [ -r $a ] is readable
if [ -s $a ] file is not 0kb
if [ -u $a ] is user allowed for file
if [ -w $a ] is writable
if [ -x $a ] is executable
more with bash
if [[ "$a" =~ "$b" ]] match (reg exp)
if [[ $a == *$b* ]] match (glob)
if [ "${a/$b}" = $a ] match (string)
if [ -z "${a##*$b*}" ] match (string, work with dropbox !)
if [ ${a/$b} = $a ] match (string)