I have this simple bash script:
I run ns simulator on each file passed in argument where last argument is some text string to search for.
#!/bin/bash
nsloc="/home/ashish/ns-allinone-2.35/ns-2.35/ns"
temp="temp12345ashish.temp"
j=1
for file in "$#"
do
if [ $j -lt $# ]
then
let j=$j+1
`$nsloc $file > $temp 2>&1`
if grep -l ${BASH_ARGV[0]} $temp
then
echo "$file Successful"
fi
fi
done
I expected:
file1.tcl Successful
I am getting:
temp12345ashish.temp
file1.tcl Successful
When i run the simulator command myself on the terminal i do not get the file name to which output is directed.
I am not getting from where this first line of output is getting printed.
Please explain it.
Thanks in advance.
See man grep, and see specifically the explanation of the -l option.
In your script (above), you are using -l, so grep is telling you (as instructed) the filename where the match occurred.
If you don't want to see the filename, don't use -l, or use -q with it also. Eg:
grep -ql ${BASH_ARGV[0]} $temp
Just silence the grep:
if grep -l ${BASH_ARGV[0]} $temp &> /dev/null
Related
I'm a rookie in bash scripting, and here's basically my bash script:
Z=`diff -Z $ref_out $exec_out | grep "[<>]" | wc -l` 2>/dev/null
if [ $Z -gt 0 ]; then
echo "*** testcase: [ stdout - FAILED ]"
else
echo "*** testcase: [ stdout - PASSED ]"
fi
I would like to suppress the error message from diff such as:
diff: No such file or directory
This could either result from no $ref_out or $exec_out file, though I'm redirecting to /dev/null, this error message still shows up.
Any help?
You need diff's stderr to go to /dev/null, so it should instead be:
Z=`diff -Z $ref_out $exec_out 2> /dev/null | grep "[<>]" | wc -l`
Your redirection isn't working because it is being applied to the parent shell, not the subshell that runs the pipeline.
If you want to send the stderr of a bunch of commands to /dev/null, you could do it this way - I am using $() instead of backticks:
Z=$( { diff -Z $ref_out $exec_out | grep "[<>]" | wc -l; } 2>/dev/null )
Here, 2>/dev/null applies to all the commands inside { }.
There are many issues in your code. You could rewrite it in a better way:
if diff -Z "$ref_out" "$exec_out" 2>/dev/null | grep -q "[<>]"; then
echo "*** testcase: [ stdout - FAILED ]"
else
echo "*** testcase: [ stdout - PASSED ]"
fi
grep -q is a better way to do this check and you won't need a wc -l unless you want to know the exact number of matches
you need to quote your variables
if statement can include commands; you don't need to capture the output in order to use it in the if statement
You can use shellcheck to validate your shell script and see if you are making the usual mistakes that can break your code.
I have been trying to get a bash script to output different things on the terminal and logfile but am unsure of what command to use.
For example,
#!/bin/bash
freespace=$(df -h / | grep -E "/" | awk '{print $4}')
greentext="\033[32m"
bold="\033[1m"
normal="\033[0m"
logdate=$(date +"%Y%m%d")
logfile="$logdate"_report.log
exec > >(tee -i $logfile)
echo -e $bold"Quick system report for "$greentext"$HOSTNAME"$normal
printf "\tSystem type:\t%s\n" $MACHTYPE
printf "\tBash Version:\t%s\n" $BASH_VERSION
printf "\tFree Space:\t%s\n" $freespace
printf "\tFiles in dir:\t%s\n" $(ls | wc -l)
printf "\tGenerated on:\t%s\n" $(date +"%m/%d/%y") # US date format
echo -e $greentext"A summary of this info has been saved to $logfile"$normal
I want to omit the last output (echo "A summary...") in the logfile while displaying it in the terminal. Is there a command to do so? It would be great if a general solution can be provided instead of a specific one because I want to apply this to other scripts.
EDIT 1 (after applying >&6):
Files in dir: 7
A summary of this info has been saved to 20160915_report.log
Generated on: 09/15/16
One option:
exec 6>&1 # save the existing stdout
exec > >(tee -i $logfile) # like you had it
#... all your outputs
echo -e $greentext"A summary of this info has been saved to $logfile"$normal >&6
# writes to the original stdout, saved in file descriptor 6 ------------^^^
The >&6 sends echo's output to the saved file descriptor 6 (the terminal, if you're running this from an interactive shell) rather than to the output path set up by tee (which is on file descriptor 1). Tested on bash 4.3.46.
References: "Using exec" and "I/O Redirection"
Edit As OP found, the >&6 message is not guaranteed to appear after the lines printed by tee off stdout. One option is to use script, e.g., as in the answers to this question, instead of tee, and then print the final message outside of the script. Per the docs, the stdbuf answers to that question won't work with tee.
Try a dirty hack:
#... all your outputs
echo >&6 # <-- New line
echo -e $greentext ... >&6
Or, equally hackish, (Note that, per OP, this worked)
#... all your outputs
sleep 0.25s # or whatever time you want <-- New line
echo -e ... >&6
I want to list the files recursively in the HOME directory. I'm trying to write my own script , so I should not use the command find or ls. My script is:
#!/bin/bash
minSize=102400;
printFiles() {
for x in "$1/"*; do
if [ -d "$x" ]; then
printFiles "$x";
else
size=$(wc -c "$x");
if [[ "$size" -gt "$minSize" ]]; then
echo "$size";
fi
fi
done
}
printFiles "/~";
So, the problem here is that when I run this script, the terminal throws Line 11: division by 0 and /home/gandalf/Videos/*: No such file or directory. I have not divided by any number, why I'm getting this error?. And the second one?
Alternatively, I can't use find or ls because I have to display the files one by one asking to the user if he want to see the next file or not. This is possible using the command find or ls or only can be done writing my own function?
Thanks.
size=$(wc -c "$x");
That's the line that is failing. When you run that wc command manually you should be able to see why:
$ wc -c /tmp/out
5 /tmp/out
The output contains not only the file size but also the file name. So you can't use $size with the -gt comparator on the next line. One way to fix that is to change the wc line to use cut (or awk, or sed, etc) to keep just the file size.
size=$(wc -c "$x" | cut -f1 -d " ")
A simpler alternative suggested by #mklement0:
size=$(wc -c < "$x")
#!/bin/bash
RESULT=$(grep -i -e "\.[a-zA-z]\{3\}$" ./test.txt)
for i in $(RESULT);
do
echo "$i"
FILENAME="$(dirname $RESULT)"
done
I have a problem with the line FILENAME="$(dirname $RESULT)". Running the script in debugging mode(bash -x script-name), the ouput is:
test.sh: line 9: RESULT: command not found
For some reason, it can't take the result of the variable RESULT and save the output of dir command to the new variable FILENAME. I can't understand why this happens.
After lots of tries, I found the solution to save full path of finame and finame to two different variables.
Now, I want for each finame, find non-case sensitive of each filename. For example, looking for file image.png, it doesn't matter if the file is image.PNG
I am running the script
while read -r name; do
echo "$name"
FILENAME="$(dirname $name)"
BASENAME="$(basename $name)"
done < <(grep -i -e "\.[a-zA-z]\{3\}$" ./test.txt)
and then enter the command:
find . $FILENAME -iname $BASENAME
but it says command FILENAME and BASENAME not found.
The syntax:
$(RESULT)
denotes command substitution. Saying so would attempt to run the command RESULT.
In order to substitute the result of the variable RESULT, say:
${RESULT}
instead.
Moreover, if the command returns more than one line of output this approach wouldn't work.
Instead say:
while read -r name; do
echo "$name"
FILENAME="$(dirname $name)"
done < <(grep -i -e "\.[a-zA-z]\{3\}$" ./test.txt)
The <(command) syntax is referred to as Process Substitution.
for i in $(RESULT) isn't right.You can use $RESULT or ${RESULT}
Okay so i have a variable called search which holds the string "Find this Code - Now". I want to search for that code and if it finds it the system would reply with true or something on those lines, if it doesn't then it just exits the script with error.
I tried to use grep but i couldn't figure out how to cut only what was searched for so i could run an if else statement
You can use the -q switch and check the exit status of grep, i.e. something like grep -q $var <file> && echo "true".
I tried to use grep but i couldn't figure out how to cut only what was searched for so i could run an if else statement
Grep has a switch --only-matching
-o, --only-matching show only the part of a line matching PATTERN
> X="not gonna find it"
> grep -qR "$X" .; echo $?
1
> X="Find this Code - Now"
> grep -qR "$X" .; echo $?
0