How to access variable declared inside the IF Condition surrounded with sudo su EOF block

Question

I have a Shell Script file name TestLog.sh Inside I have a variable assigned with some value inside IF condition. I want to access that variable outside IF condition in the same file.

#!/bin/sh

sudo su <<EOF
if [ $# -eq 0 ]; then
LOG_LOCATION="Base/reports/jtl_logs"
CSV_LOCATION="Base/reports/csv"
LOOP_COUNT=30
elif [ $# -eq 1 ]; then
LOG_LOCATION="Base/reports/$1/jtl_logs"
CSV_LOCATION="Base/reports/$1/csv"
LOOP_COUNT=30
elif [ $# -eq 2 ]; then
LOG_LOCATION="Base/reports/$1/jtl_logs"
CSV_LOCATION="Base/reports/$1/csv"
LOOP_COUNT=$2
fi

echo $LOG_LOCATION
echo $CSV_LOCATION
echo $LOOP_COUNT
EOF

I call my script as

TestLog.sh 19.10.11 3

Expected Output:

Base/reports/19.10.11/jtl_logs
Base/reports/19.10.11/csv
3

Actual Output:

Display nothing

I don't see any `if` in your code; I see only `elif` and `fi`. Please post the complete code. — user1934428, Aug 05 '19 at 15:16
Done. Seems like formatting issue. Lets me know if anything is needed. — Munish Prabhu, Aug 05 '19 at 17:11
[Can't reproduce](https://tio.run/##S0kszvj/X1lRPykzT784g4srM00hWkFFWUE3tVDBQCHWWqEkIzWPy8ffPd7H39kxxNPfz1bJKbE4Vb8otSC/qKRYP6skJz4nP71Yics5OAyXouTiMiWgIf4B8c7@oX4htsYGXKk5yFYZEmOViiFxtgHVEbTQiMYWqhhxpWVycaUmZ@QrqCBbARVCNg2uCqb7////hpZ6hgZ6hob/jQE). — melpomene, Aug 05 '19 at 17:24
Provides **Expected Output:** here. What OS? Please show the output of `sh --version`. Also show output of `ls -al TestLog.sh`. — David C. Rankin, Aug 05 '19 at 18:40
Sorry @melpomene. IF condition is surrounded inside sudo su EOF block. Have updated the code snippet — Munish Prabhu, Aug 05 '19 at 18:49
Variables you set in one shell are not visible in another shell process. — melpomene, Aug 05 '19 at 19:11
But IF condition and echo statements are in same shell right? — Munish Prabhu, Aug 05 '19 at 19:18

KamilCuk · Answer 1 · 2019-08-05T21:55:12.307

sudo su <<EOF

The expansion of the variables inside here document with unquoted "limit string" (the <<EOF part) happens before the sudo command is executed.

a=1
sudo <<EOF
a=2
echo $a
EOF

The $a above is expanded first, so first it looks like:

sudo <<'EOF'
a=2
echo 1
EOF

then sudo command is run with the input.

You can force the shell not to expand the variables inside the here document by quoting the limit string. As I showed above with <<'EOF'. If the limit string is quoted, no expansion happens inside, the text is taken as it is. But that would make you jump into another problem - the $# will be 0 inside sudo, cause you didn't pass any parameters.

Also sudo su makes no sense. Just sudo or just su.

One solution could be such a construct:

sudo sh -c '
if [ $# -eq 0 ]; then
  LOG_LOCATION="Base/reports/jtl_logs"
  CSV_LOCATION="Base/reports/csv"
  LOOP_COUNT=30
elif [ $# -eq 1 ]; then
  LOG_LOCATION="Base/reports/$1/jtl_logs"
  CSV_LOCATION="Base/reports/$1/csv"
  LOOP_COUNT=30
elif [ $# -eq 2 ]; then
  LOG_LOCATION="Base/reports/$1/jtl_logs"
  CSV_LOCATION="Base/reports/$1/csv"
  LOOP_COUNT=$2
fi

echo $LOG_LOCATION
echo $CSV_LOCATION
echo $LOOP_COUNT
' -- "$@"

You can run a shell inside sudo and pass the script using -c option and specify the arguments to the shell. The quoting get's really hard, as you are inside quotes.

Alternatively and safer, you could create a temporary file, run it and remove it after your script execution. This let's you a bit more control.

cat >/tmp/tempfile.sh <<'EOF'
#!/bin/sh
if [ $# -eq 0 ]; then
  LOG_LOCATION="Base/reports/jtl_logs"
  CSV_LOCATION="Base/reports/csv"
  LOOP_COUNT=30
elif [ $# -eq 1 ]; then
  LOG_LOCATION="Base/reports/$1/jtl_logs"
  CSV_LOCATION="Base/reports/$1/csv"
  LOOP_COUNT=30
elif [ $# -eq 2 ]; then
  LOG_LOCATION="Base/reports/$1/jtl_logs"
  CSV_LOCATION="Base/reports/$1/csv"
  LOOP_COUNT=$2
fi

echo $LOG_LOCATION
echo $CSV_LOCATION
echo $LOOP_COUNT
EOF

sudo sh /tmp/tempfile.sh "$@"

rm /tmp/tempfile.sh

Or you could well pass the parameters to what you have now by specifying the input script for shell to be stdin:

sudo sh /dev/stdin "$@" <<'EOF'
if [ $# -eq 0 ]; then
LOG_LOCATION="Base/reports/jtl_logs"
CSV_LOCATION="Base/reports/csv"
LOOP_COUNT=30
elif [ $# -eq 1 ]; then
LOG_LOCATION="Base/reports/$1/jtl_logs"
CSV_LOCATION="Base/reports/$1/csv"
LOOP_COUNT=30
elif [ $# -eq 2 ]; then
LOG_LOCATION="Base/reports/$1/jtl_logs"
CSV_LOCATION="Base/reports/$1/csv"
LOOP_COUNT=$2
fi

echo $LOG_LOCATION
echo $CSV_LOCATION
echo $LOOP_COUNT
EOF

I don't like all three options specified above. Running such long scripts under sudo feels very unsafe. All the ifs inside sudo look strange - why would you check the $# inside sudo? Why not do it in parent shell and only pass parsed variables to the command you only need to run via sudo? This feels like it violates a lot of least privilege principle - the ifs nor the echos, they doesn't need to be run as root at all.

How to access variable declared inside the IF Condition surrounded with sudo su EOF block

1 Answers1