Why isn't this bash array populating? I believe I've done them like this in the past. Echoing ${#XECOMMAND[#]} shows no data..
DIR=$1
TEMPFILE=/tmp/dir.tmp
ls -l $DIR | tail -n +2 | sed 's/\s\+/ /g' | cut -d" " -f5,9 > $TEMPFILE
i=0
cat $TEMPFILE | while read line ;do
if [[ $(echo $line | cut -d" " -f1) == 0 ]]; then
XECOMMAND[$i]="$(echo "$line" | cut -d" " -f2)"
(( i++ ))
fi
done
When you run the while loop like
somecommand | while read ...
then the while loop is executed in sub-shell, i.e. a different process than the main script. Thus, all variable assignments that happen in the loop, will not be reflected in the main process. The workaround is to use input redirection and/or command substitution, so that the loop executes in the current process. For example if you want to read from a file you do
while read ....
do
# do stuff
done < "$filename"
or if you wan't the output of a process you can do
while read ....
do
# do stuff
done < <(some command)
Finally, in bash 4.2 and above, you can set shopt -s lastpipe, which causes the last command in the pipeline to be executed in the current process.
I think you're trying to construct an array consisting of the names of all zero-length files and directories in $DIR. If so, you can do it like this:
mapfile -t ZERO_LENGTH < <(find "$DIR" -maxdepth 1 -size 0)
(Add -type f to the find command if you're only interested in regular files.)
This sort of solution is almost always better than trying to parse ls output.
The use of process substitution (< <(...)) rather than piping (... |) is important, because it means that the shell variable will be set in the current shell, not in an ephimeral subshell.
I have been trying to split up a string and putting it into an Array in Bash on my Mac without success.
Here is my sample code:
#!/bin/bash
declare -a allDisks
allDisksString="`ls /dev/disk* | grep -e 'disk[0-9]s.*' | awk '{ print $NF }'`"
#allDisksString="/dev/disk0s1 /dev/disk1s1"
echo allDisksString is $allDisksString
IFS=' ' read -ra allDisks <<< "$allDisksString"
echo allDIsks is "$allDisks"
echo The second item in allDisks is "${allDisks[1]}"
for disk in "${allDisks[#]}"
do
printf "Loop $disk\n"
done
And below is the output:
allDisksString is /dev/disk0s1 /dev/disk0s2 /dev/disk0s3 /dev/disk0s4 /dev/disk1s1
allDIsks is /dev/disk0s1
The second item in allDisks is
Loop /dev/disk0s1
Interesting if I execute the following in the Mac Terminal:
ls /dev/disk* | grep -e 'disk[0-9]s.*' | awk '{ print $NF }'
I get the following output
/dev/disk0s1
/dev/disk0s2
/dev/disk0s3
/dev/disk0s4
/dev/disk1s1
So I have also tried setting IFS to IFS=$'\n' without any success.
So no luck in getting a list of my drives into an array.
Any ideas on what I am doing wrong?
You're making this much more complicated than it needs to be. You don't need to use ls, you can just use a wildcard to match the device names you want, and put that in an array assignment.
#!/bin/bash
declare -a allDisks
allDisks=(/dev/disk[0-9]s*)
echo allDIsks is "$allDisks"
echo The second item in allDisks is "${allDisks[1]}"
for disk in "${allDisks[#]}"
do
printf "Loop $disk\n"
done
read only reads one line.
Use an assignment instead. When assigning to an array, you need to use parentheses after the = sign:
#!/bin/bash
disks=( $(ls /dev/disk* | grep -e 'disk[0-9]s.*' | awk '{ print $NF }') )
echo ${disks[1]}
The below script:
#!/bin/bash
otscurrent="
AAA,33854,4528,38382,12
BBB,83917,12296,96213,13
CCC,20399,5396,25795,21
DDD,27198,4884,32082,15
EEE,2472,981,3453,28
FFF,3207,851,4058,21
GGG,30621,4595,35216,13
HHH,8450,1504,9954,15
III,4963,2157,7120,30
JJJ,51,59,110,54
KKK,87,123,210,59
LLL,573,144,717,20
MMM,617,1841,2458,75
NNN,234,76,310,25
OOO,12433,1908,14341,13
PPP,10627,1428,12055,12
QQQ,510,514,1024,50
RRR,1361,687,2048,34
SSS,1,24,25,96
TTT,0,5,5,100
UUU,294,1606,1900,85
"
IFS="," array1=(${otscurrent})
echo ${array1[4]}
Prints:
$ ./test.sh
12
BBB
I'm trying to get it to just print 12... And I am not even sure how to make it just print row 5 column 4
The variable is an output of a sqlquery that has been parsed with several sed commands to change the formatting to csv.
otscurrent="$(sqlplus64 user/password#dbserverip/db as sysdba #query.sql |
sed '1,11d; /^-/d; s/[[:space:]]\{1,\}/,/g; $d' |
sed '$d'|sed '$d'|sed '$d' | sed '$d' |
sed 's/Used,MB/Used MB/g' |
sed 's/Free,MB/Free MB/g' |
sed 's/Total,MB/Total MB/g' |
sed 's/Pct.,Free/Pct. Free/g' |
sed '1b;/^Name/d' |
sed '/^$/d'
)"
Ultimately I would like to be able to call on a row and column and run statements on the values.
Initially i was piping that into :
awk -F "," 'NR>1{ if($5 < 10) { printf "%-30s%-10s%-10s%-10s%-10s\n", $1,$2,$3,$4,$5"%"; } else { echo "Nothing to do" } }')"
Which works but I couldn't run commands from if else ... or atleaste I didn't know how.
If you have bash 4.0 or newer, an associative array is an appropriate way to store data in this kind of form.
otscurrent=${otscurrent#$'\n'} # strip leading newline present in your sample data
declare -A data=( )
row=0
while IFS=, read -r -a line; do
for idx in "${!line[#]}"; do
data["$row,$idx"]=${line[$idx]}
done
(( row += 1 ))
done <<<"$otscurrent"
This lets you access each individual item:
echo "${data[0,0]}" # first field of first line
echo "${data[9,0]}" # first field of tenth line
echo "${data[9,1]}" # second field of tenth line
"I'm trying to get it to just print 12..."
The issue is that IFS="," splits on commas and there is no comma between 12 and BBB. If you want those to be separate elements, add a newline to IFS. Thus, replace:
IFS="," array1=(${otscurrent})
With:
IFS=$',\n' array1=(${otscurrent})
Output:
$ bash test.sh
12
All you need to print the value of the 4th column on the 5th row is:
$ awk -F, 'NR==5{print $4}' <<< "$otscurrent"
3453
and just remember that in awk row (record) and column (field) numbers start at 1, not 0. Some more examples:
$ awk -F, 'NR==1{print $5}' <<< "$otscurrent"
12
$ awk -F, 'NR==2{print $1}' <<< "$otscurrent"
BBB
$ awk -F, '$5 > 50' <<< "$otscurrent"
JJJ,51,59,110,54
KKK,87,123,210,59
MMM,617,1841,2458,75
SSS,1,24,25,96
TTT,0,5,5,100
UUU,294,1606,1900,85
If you'd like to avoid all of the complexity and simply parse your SQL output to produce what you want without 20 sed commands in between, post a new question showing the raw sqlplus output as the input and what you want finally output and someone will post a brief, clear, simple, efficient awk script to do it all at one time, or maybe 2 commands if you still want an intermediate CSV for some reason.
I need to assign two columns (column 2 and 6) in a text file to a variable as an array. so that i can call them back element by element.
the code below puts the whole column as one string element in k and l.
and the echo command will not return anything as everything is stored in the first element
k=`(cat mydata.txt | awk '{print $2}')`
l=`(cat mydata.txt | awk '{print $6}')`
echo ${k[2]}
echo ${l[2]}
below is an example of data set i used.
60594412 56137844 48552535 44214019 44121294 28652826 21975449 21718959 18208824 18004925 13299946 12969796 11990006 10435260 9992615 9975420 9223972 8918246 8730367 7723045 7316105 6772270 6301570 5662296 4653831 3769516 3343899 2639162 2393169 1992206 1838674 1681498 1563810 1389679 1267762 1253490 1205487 940968 718249 702722 655069 649121 619911 437735 284727 264334 252627 233213 185924 177421 160412 156581 143128 107247 87194 81369 74594 74185
Swap the order of the parentheses and backticks.
k=(`cat mydata.txt | awk '{print $2}'`)
l=(`cat mydata.txt | awk '{print $6}'`)
Stylewise, you could get rid of the useless use of cat and also change the backticks to $(...), which is generally preferable.
k=( $(awk '{print $2}' mydata.txt) )
l=( $(awk '{print $6}' mydata.txt) )
I need to know how many processes are running for a specific task (e.g. number of Apache tomcats) and if it's 1, then print the PID. Otherwise print out a message.
I need this in a BASH script, now when I perform something like:
result=`ps aux | grep tomcat | awk '{print $2}' | wc -l`
The number of items is assigned to result. Hurrah! But I don't have the PID(s). However when I attempt to perform this as an intermediary step (without the wc), I encounter problems. So if I do this:
result=`ps aux | grep tomcat | awk '{print $2}'`
Any attempts I make to modify the variable result just don't seem to work. I've tried set and tr (replace blanks with line-breaks), but I just cannot get the right result. Ideally I'd like the variable result to be an array with the PIDs as individual elements. Then I can see size, elements, easily.
Can anyone suggest what I am doing wrong?
Thanks,
Phil
Update:
I ended up using the following syntax:
pids=(`ps aux | grep "${searchStr}"| grep -v grep | awk '{print $2}'`)
number=${#pids[#]}
The key was putting the brackets around the back-ticked commands. Now the variable pids is an array and can be asked for length and elements.
Thanks to both choroba and Dimitre for their suggestions and help.
pids=($(
ps -eo pid,command |
sed -n '/[t]omcat/{s/^ *\([0-9]\+\).*/\1/;p}'
))
number=${#pids[#]}
pids=( ... ) creates an array.
$( ... ) returns its output as a string (similar to backquote).
Then, sed is called on the list of all the processes: for lines containing tomacat (the [t] prevents the sed itself from being included), only the pid is preserved and printed.
You may need to adjust the pgrep command (you may need or may not need the -f option).
_pids=(
$( pgrep -f tomcat )
)
(( ${#_pids[#]} == 1 )) &&
echo ${_pids[0]} ||
echo message
If you want to print the number of pids (with a message):
_pids=(
$( pgrep -f tomcat )
)
(( ${#_pids[#]} == 1 )) &&
echo ${_pids[0]} ||
echo "${#_pids[#]} running"
It should be noted that the pgrep utility and the syntax used are not standard.