I'm writing a simple program to add a contact into a file called "phonebook", but if the contact already exists, i want it to return an echo saying " (first name last name) already exists", and not add it to the file. So far, i've gotten the program to add the user, but it wont return that echo and adds the duplicate entry anyway. How can i fix this?
#!/bin/bash
# Check that 5 arguments are passed
#
if [ "$#" -ne 5 ]
then
echo
echo "Usage: first_name last_name phone_no room_no building"
echo
exit 1
fi
first=$1
last=$2
phone=$3
room=$4
building=$5
# Count the number of times the input name is in add_phonebook
count=$( grep -i "^$last:$first:" add_phonebook | wc -l )
#echo $count
# Check that the name is in the phonebook
if [ "$count" -eq 1 ]
then
echo
echo "$first $last is already in the phonebook."
echo
exit 1
fi
# Add someone to the phone book
#
echo "$1 $2 $3 $4 $5" >> add_phonebook
# Exit Successfully
exit 0
Couple of things:
Should check if add_phonebook file exists before attempting to grep it, otherwise you get the grep: add_phonebook: No such file or directory output.
Your grep expression doesn't match the format of the file.
You are saving the file with space in between the fields, but searching with a colon(:) between the names. You can either update the file format to use a colon to separate the fields, or update the grep expression to search on space. In addition, you save first name, last_name, but search on last_name, first_name.
With space format:
count=$( grep -i "^$last[[:space:]]\+$first[[:space:]]" add_phonebook | wc -l )
Removed my tab separators from the echo line, used spaces, and now it can count properly
Related
I am trying to create a bash script that will generate an SQL CREATE TABLE statement from a CSV file.
#!/bin/bash
# Check if the user provided a CSV file
if [ $# -eq 0 ]
then
echo "No CSV file provided."
exit 1
fi
# Check if the CSV file exists
if [ ! -f $1 ]
then
echo "CSV file does not exist."
exit 1
fi
# Get the table name from the CSV file name
table_name=$(basename $1 .csv)
# Extract the header row from the CSV file
header=$(head -n 1 $1)
# Split the header row into column names
IFS=',' read -r -a columns <<< "$header"
# Generate the PostgreSQL `CREATE TABLE` statement
echo "CREATE TABLE $table_name ("
for column in "${columns[#]}"
do
echo " $column TEXT,"
done
echo ");"
If I have a CSV file with three columns(aa,bb,cc), the generated statement does not have the last column for some reason.
Any idea what could be wrong?
If I do:
for a in "${array[#]}"
do
echo "$a"
done
I am getting:
aaa
bbb
ccc
But when add something into the string:
for a in "${array[#]}"
do
echo "$a SOMETHING"
done
I get:
aaa SOMETHING
bbb SOMETHING
SOMETHING
Thanks.
Your csv file has a '\r`
Try the next block for reproducing the problem.
printf -v header "%s,%s,%s\r\n" "aaa" "bbb" "ccc"
IFS=',' read -r -a columns <<< "$header"
echo "Show array"
for a in "${columns[#]}"; do echo "$a"; done
echo "Now with something extra"
for a in "${columns[#]}"; do echo "$a SOMETHING"; done
You should remove the '\r', what can be done with
IFS=',' read -r -a columns < <(tr -d '\r' <<< "${header}")
I'm writing a unix script which does an awk and pipes to a while loop. For some reason, though, the while loop iterates only once. Can someone point out what I am missing?
awk '{ print $1, $2}' file |
while IFS=" " read A B
do
echo $B
if [ "$B" -eq "16" ];
then
grep -A 1 $A $1 | python unreverse.py
else
grep -A 1 $A
fi
done
"file" looks something like
cheese 2
elephant 5
tiger 16
Solution
The solution is to replace:
grep -A 1 $A
With:
grep -A 1 "$A" filename
Where filename is whatever file you intended grep to read from. Just guessing, maybe you intended:
grep -A 1 "$A" "$1"
I added double-quotes to prevent any possible word-splitting.
Explanation
The problem is that, without the filename, the grep command reads from and consumes all of standard input. It does this on the first run through the loop. Consequently, there is not input left for the second run and read A B fails and the loop terminates.
A Simpler Example
We can see the same issue happening with many fewer statements. Here is a while loop that is given two lines of input but only loops once:
$ { echo 1; echo 2; } | while read n; do grep "$n"; echo "n=$n"; done
n=1
Here, simply by adding a filename to the grep statement, we see that the while loop executes twice, as it should:
$ { echo 1; echo 2; } | while read n; do grep "$n" /dev/null; echo "n=$n"; done
n=1
n=2
How can I check the return value of "Find" statement in shell script
I am use Find in my script , if find statement don't find any file the execute exit !!
I want to check the return value of "Find" if it found any files or not
You can redirect output of the find command to a file called say output.txt then you can check if the size of that file is 0 or not by using -s option;
if [[ -s "output.txt" ]]
then
echo "File is not empty!"
else
echo "File is empty!"
fi
You can count the number of files found by find using the wc -l command:
export result=`find . -name *.txt | wc -l`
You can now check result to see how many files where found
if [ $result == "0" ]; then echo zero found; fi
I have a small script that simply reads each line of a file, retrieves id field, runs utility to get the name and appends the name at the end. The problem is the input file is huge (2GB). Since output is same as input with a 10-30 char name appended, it is of the same order of magnitude. How can I optimize it to read large buffers, process in buffers and then write buffers to the file so the number of file accesses are minimized?
#!/bin/ksh
while read line
do
id=`echo ${line}|cut -d',' -f 3`
NAME=$(id2name ${id} | cut -d':' -f 4)
if [[ $? -ne 0 ]]; then
NAME="ERROR"
echo "Error getting name from id2name for id: ${id}"
fi
echo "${line},\"${NAME}\"" >> ${MYFILE}
done < ${MYFILE}.csv
Thanks
You can speed things up considerably by eliminating the two calls to cut in each iteration of the loop. It also might be faster to move the redirection to your output file to the end of the loop. Since you don't show an example of an input line, or what id2name consists of (it's possible it's a bottleneck) or what its output looks like, I can only offer this approximation:
#!/bin/ksh
while IFS=, read -r field1 field2 id remainder # use appropriate var names
do
line=$field1,$field2,$id,$remainder
# warning - reused variables
IFS=: read -r field1 field2 field3 NAME remainder <<< $(id2name "$id")
if [[ $? -ne 0 ]]; then
NAME="ERROR"
# if you want this message to go to stderr instead of being included in the output file include the >&2 as I've done here
echo "Error getting name from id2name for id: ${id}" >&2
fi
echo "${line},\"${NAME}\""
done < "${MYFILE}.csv" > "${MYFILE}"
The OS will do the buffering for you.
Edit:
If your version of ksh doesn't have <<<, try this:
id2name "$id" | IFS=: read -r field1 field2 field3 NAME remainder
(If you were using Bash, this wouldn't work.)
I currently have a request to build a shell script to get some data from the table using SQL (Oracle). The query which I'm running return a number of rows. Is there a way to use something like result set?
Currently, I'm re-directing it to a file, but I'm not able to reuse the data again for the further processing.
Edit: Thanks for the reply Gene. The result file looks like:
UNIX_PID 37165
----------
PARTNER_ID prad
--------------------------------------------------------------------------------
XML_FILE
--------------------------------------------------------------------------------
/mnt/publish/gbl/backup/pradeep1/27241-20090722/kumarelec2.xml
pradeep1
/mnt/soar_publish/gbl/backup/pradeep1/11089-20090723/dataonly.xml
UNIX_PID 27654
----------
PARTNER_ID swam
--------------------------------------------------------------------------------
XML_FILE
--------------------------------------------------------------------------------
smariswam2
/mnt/publish/gbl/backup/smariswam2/10235-20090929/swam2.xml
There are multiple rows like this. My requirement is only to use shell script and write this program.
I need to take each of the pid and check if the process is running, which I can take care of.
My question is how do I check for each PID so I can loop and get corresponding partner_id and the xml_file name? Since it is a file, how can I get the exact corresponding values?
Your question is pretty short on specifics (a sample of the file to which you've redirected your query output would be helpful, as well as some idea of what you actually want to do with the data), but as a general approach, once you have your query results in a file, why not use the power of your scripting language of choice (ruby and perl are both good choices) to parse the file and act on each row?
Here is one suggested approach. It wasn't clear from the sample you posted, so I am assuming that this is actually what your sample file looks like:
UNIX_PID 37165 PARTNER_ID prad XML_FILE /mnt/publish/gbl/backup/pradeep1/27241-20090722/kumarelec2.xml pradeep1 /mnt/soar_publish/gbl/backup/pradeep1/11089-20090723/dataonly.xml
UNIX_PID 27654 PARTNER_ID swam XML_FILE smariswam2 /mnt/publish/gbl/backup/smariswam2/10235-20090929/swam2.xml
I am also assuming that:
There is a line-feed at the end of
the last line of your file.
The columns are separated by a single
space.
Here is a suggested bash script (not optimal, I'm sure, but functional):
#! /bin/bash
cat myOutputData.txt |
while read line;
do
myPID=`echo $line | awk '{print $2}'`
isRunning=`ps -p $myPID | grep $myPID`
if [ -n "$isRunning" ]
then
echo "PARTNER_ID `echo $line | awk '{print $4}'`"
echo "XML_FILE `echo $line | awk '{print $6}'`"
fi
done
The script iterates through every line (row) of the input file. It uses awk to extract column 2 (the PID), and then does a check (using ps -p) to see if the process is running. If it is, it uses awk again to pull out and echo two fields from the file (PARTNER ID and XML FILE). You should be able to adapt the script further to suit your needs. Read up on awk if you want to use different column delimiters or do additional text processing.
Things get a little more tricky if the output file contains one row for each data element (as you indicated). A good approach here is to use a simple state mechanism within the script and "remember" whether or not the most recently seen PID is running. If it is, then any data elements that appear before the next PID should be printed out. Here is a commented script to do just that with a file of the format you provided. Note that you must have a line-feed at the end of the last line of input data or the last line will be dropped.
#! /bin/bash
cat myOutputData.txt |
while read line;
do
# Extract the first (myKey) and second (myValue) words from the input line
myKey=`echo $line | awk '{print $1}'`
myValue=`echo $line | awk '{print $2}'`
# Take action based on the type of line this is
case "$myKey" in
"UNIX_PID")
# Determine whether the specified PID is running
isRunning=`ps -p $myValue | grep $myValue`
;;
"PARTNER_ID")
# Print the specified partner ID if the PID is running
if [ -n "$isRunning" ]
then
echo "PARTNER_ID $myValue"
fi
;;
*)
# Check to see if this line represents a file name, and print it
# if the PID is running
inputLineLength=${#line}
if (( $inputLineLength > 0 )) && [ "$line" != "XML_FILE" ] && [ -n "$isRunning" ]
then
isHyphens=`expr "$line" : -`
if [ "$isHyphens" -ne "1" ]
then
echo "XML_FILE $line"
fi
fi
;;
esac
done
I think that we are well into custom software development territory now so I will leave it at that. You should have enough here to customize the script to your liking. Good luck!