I want a script to run a main.ksh to run both one.ksh and second.ksh only if output of one.ksh matches "1". So if the output is anything other than "1" then second.ksh shouyld not run.
cat one.ksh
#!/usr/bin/ksh
echo "1"
cat second.ksh
#!/usr/bin/ksh
echo "2"
I did this:
#!/usr/bin/ksh
ksh .ksh > one.txt
file="one.txt"
while read line
do
if [ $line -eq 2 ] ;then
ksh second.ksh
else
echo "one.ksh is no good"
fi
done <"$file"
Any better way ro this is good?
Instead of echo 1 to proceed from the first script, you should use exit 0. If it shouldn't proceed, exit 1.
This is the standard way of signaling success and failure in Unix.
Once you do this, you can use any of:
first.ksh && second.ksh
or
if first.ksh
then
second.ksh
fi
or
set -e # Automatically exit script if a command fails
first.ksh
second.ksh
out=`one.ksh`
if [ "x$out" == "x1" ]; then
second.ksh
fi
Related
I'm trying to implement a bash script who supposed to search for a word in a Python script terminal output.
The Python script doesn't stop so "&" in the end of the command is needed but the "if [ $? == 0 ] ; then" condition doesn't work.
How it can be solved?
Thanks, Gal.
#!/bin/bash
#Check if Pixhawk is connected
PORT=/dev/ttyPixhawk
end=$((SECONDS+3))
not_exists=f
/usr/local/bin/mavproxy.py --daemon --non-interactive --master=$PORT | grep 'Failed' &> /dev/null &
while [ $SECONDS -lt $end ] ; do
if [ $? == 0 ] ; then
not_exists=t
fi
sleep 1
done
if [ $not_exists=t ] ; then
echo "Not Exists"
else
echo "Exists"
fi
kill $(pgrep -f '/usr/local/bin/mavproxy.py')
Bash doesn't know anything about the output of background commands. Check for yourself with [ 5444 -lt 3 ] & echo $?.
your if statement wouldn't work in any case because $? checks for the return value of the most recent previous command, which in this case is your while loop.
You have a few different options. If you're waiting for some output, and you know how long it is in the output until whatever target you're looking for occurs, you can have the python write to a file and keep checking on the file size with a timeout for failure.
You can also continue with a simple timed approach as you have where you just check the output after a few seconds and decide success or failure based on that.
You can make your python script actually end, or provide more error messages, or write only the relevant parts to file that way.
Furthermore, you really should run your script through shellcheck.net to notice more problems.
You'll need to define your goal and use case more clearly to get real help; all we can really say is "your approach will not work, but there are definitely approaches which will work"
You are checking the status of grep command output inside while loop using $?. This can be done if $? is the next command to be fired after grep and if grep is not a back-group process . But in your script, $? will return the status of while [$SECONDS -lt $end ]. You can try to re-direct the output to a temp file and check it's status
/usr/local/bin/mavproxy.py --daemon --non-interactive --master=$PORT | grep 'Failed' &> tmp.txt &
sleep 3
# If file exists and it's size is greater than 0, [ -s File] will return true
if [ -s tmp.txt ]; then
echo 'pattern exists'
else
echo 'pattern not exists'
fi
I am running club.sh
inside club.sh script i am running below scripts.
test1.sh
test2.sh
test3.sh
my concern is it should run one by one and if test1 fails it will not run test2.sh and if test2.sh fails it willnot run test3.sh
how can we check? can any one suggest any idea it would be very helpful.
Thanks,
Two approaches -
First, you can examine the exit code of each of your inner scripts (test1.sh, test2.sh, ...) and decide whether to continue accordingly -
$? Will return the exit code of the previous command. It will be 0 (zero) if the script exited without an error. Anything that is not 0 can be considered a failure. So you could so something like this -
./test1.sh # execute script
if [[ $? != 0 ]]; then exit; fi # check return value, exit if not 0
Alternatively, you could use the && bash operator which will only execute subsequent commands if the previous one passed -
./test1.sh && ./test2.sh && test3.sh
Only if test1.sh returns an exit code of 0 (zero) will test2.sh execute and the same goes for test3.sh.
The first approach is good if you need to do some logging or cleanup between executing your scripts, but if you are only concerned that the execution should not continue if there was a failure then the && method would be they way I recommend.
Here is a related post dealing with the meaning behind &&
The returned value of the execution of the first command/script is stored in $? so using this value you can check if your command was successfully executed.
Try this:
bash test1.sh
if [ $? -eq 0 ]; then # if script succeeded
bash test2.sh
else
echo "script failed"
fi
If you want to exit your script whenever a command fails, you just add at the beginning of your script set -e.
#!/bin/bash
set -e
echo hello
ls /root/lalala
echo world
Otherwise, you have two options.
The first one is to use &&. For instance:
echo hello && ls /some_inexistant_directory && echo world
The second one is to check the return value after each command:
#!/bin/bash
echo toto
if [ "$?" != "0" ]; then
exit 1
fi
ls /root
if [ "$?" != "0" ]; then
exit 1
fi
echo world
if [ "$?" != "0" ]; then
exit 1
fi
You just have to put the below at the begging of the script:
#!/bin/bash -e
I have the following unix shell script, in which i have two integer
variables namely a and b.
If a is greater then or equal to b then shell script should exit with returning 0.
Else it should exit with returning 1.
My try:
Script: ConditionTest.sh
#!/bin/sh
a=10
b=20
if [ $a -ge $b ]
then
exit 0
else
exit 1
fi
....
....
....
Running Script:
$ ./ConditionTest.sh
$
Note: I am not getting any return value after executing the file.
The shell puts the exit status of the last command in the variable ?.
You could simply inspect it:
mycommand
echo $?
... or you could use it to do something else depending on its value:
mycommand && echo "ok" || echo "failed"
or alternatively, and slightly more readable:
if mycommand; then
# exit with 0
echo "ok"
else
# exit with non-zero
echo "failed"
if
Your script looks fine; you did everything right.
#!/bin/sh
a=10
b=20
if [ $a -ge $b ]
then
exit 0
else
exit 1
fi
So here's where we run it and check the return value:
$ sh test.sh
$ echo $?
1
$
10 is not greater than or equal to 20.
Another way to test it would be like this:
$ sh test.sh && echo "succeeded" || echo "failed"
failed
As noted in the comments, you should also quote your variables, always:
if [ $a -ge $b ]
Should be:
if [ "$a" -ge "$b" ]
To add to the previous answers, the key idea you should understand is that every program provides a number when exiting. That number is used as a way to report if the command has completed its operation successfully, and if not, what type of error has occurred.
Like mentioned, the exit code of the last command executed can be accessed with $?.
The reason nothing was printed by your script, is that your script returned 1, but the exit code of a command is not printed. (This is analogous to calling a function, you get a return value from the function but it's not printed)
So I started today taking a look at scripting using vim and I'm just so very lost and was looking for some help in a few areas.
For my first project,I want to process a file as a command line argument, and if a file isn't included when the user executes this script, then a usage message should be displayed, followed by exiting the program.
I have no clue where to even start with that, will I need and if ... then statement, or what?
Save vim for later and try to learn one thing at a time. A simpler text editor is called nano.
Now, as far as checking for a file as an argument, and showing a usage message otherwise, this is a typical pattern:
PROGNAME="$0"
function show_usage()
{
echo "Usage: ${PROGNAME} <filename>" >&2
echo "..." >&2
exit 1
}
if [[ $# -lt 1 ]]; then
show_usage
fi
echo "Contents of ${1}:"
cat "$1"
Let's break this down.
PROGNAME="$0"
$0 is the name of the script, as it was called on the command line.
function show_usage()
{
echo "Usage: ${PROGNAME} <filename>" >&2
echo "..." >&2
exit 1
}
This is the function that prints the "usage" message and exits with a failure status code. 0 is success, anything other than 0 is a failure. Note that we redirect our echo to &2--this prints the usage message on Standard Error rather than Standard Output.
if [[ $# -lt 1 ]]; then
show_usage
fi
$# is the number of arguments passed to the script. If that number is less than 1, print the usage message and exit.
echo "Contents of ${1}:"
cat "$1"
$1 is out filename--the first argument of the script. We can do whatever processing we want to here, with $1 being the filename. Hope this helps!
i think you're asking how to write a bash script that requires a file as a command-line argument, and exits with a usage message if there's a problem with that:
#!/bin/bash
# check if user provided exactly one command-line argument:
if [ $# -ne 1 ]; then
echo "Usage: `basename "$0"` file"
exit 1
# now check if the provided argument corresponds to a real file
elif [ ! -f "$1" ]; then
echo "Error: couldn't find $1."
exit 1
fi
# do things with the file...
stat "$1"
head "$1"
tail "$1"
grep 'xyz' "$1"
I have a shell script where I pass (2) parameters, one to pass a dbname, the other to call one of (2) filenames. I want to check if either filename exists, then proceed with calling that script, else exit because the user can enter the wrong string and construct my_foo.sql which I don't want. I don't think I have the condition for setting "or" correctly since putting the correct param still produces error. Is there a better way to write this?
Here is what I have so far.
#/usr/bin/ksh
if [ $# != 2 ]; then
echo "Usage: test.sh <dbname> <test|live>" 2>&1
exit 1
fi
# Check actual file name
CHKSCRIPT1=/tmp/my_test.sql;
CHKSCRIPT2=/tmp/my_live.sql;
if [ -f "CHKSCRIPT1" ] || [ -f "CHKSCRIPT2" ]
then
/bin/sqlplus -s foo/bar #/my_$2.sql
else
echo "Correct sql script does not exist. Enter test or live"
exit 1
fi
Your issue is that you're not referencing your variables correctly:
if [ -f "$CHKSCRIPT1" ] || [ -f "$CHKSCRIPT2" ]
...
fi
edit: Per #chepner, you shouldn't use -o
In addition to the problem you had with expanding the parameters, you should separate what the user types from what files need to exist. If the user enters "live", the only thing that matters is whether or not /tmp/my_live.sql exists. If the user enters "injection_attack", your script should not execute /tmp/my_injection_attack.sql (which presumably was created without your knowledge). The right thing to do is to first verify that a valid command was entered, then check if the appropriate file exists.
if [ $# != 2 ]; then
echo "Usage: test.sh <dbname> <test|live>" 2>&1
exit 1
fi
case $2 in
test|live)
filename="/tmp/my_{$2}.sql"
;;
*) echo "Must enter test or live"
exit 1
;;
esac
if [ -f "$filename" ]; then
/bin/sqlplus -s foo/bar #/my_$2.sql
else
echo "SQL script $filename does not exist."
exit 1
fi