Reading a file line by line in ksh - ksh

We use some package called Autosys and there are some specific commands of this package. I have a list of variables which i like to pass in one of the Autosys commands as variables one by one.
For example one such variable is var1, using this var1 i would like to launch a command something like this
autosys_showJobHistory.sh var1
Now when I launch the below written command, it gives me the desired output.
echo "var1" | while read line; do autosys_showJobHistory.sh $line | grep 1[1..6]:[0..9][0..9] | grep 24.12.2012 | tail -1 ; done
But if i put the var1 in a file say Test.txt and launch the same command using cat, it gives me nothing. I have the impression that command autosys_showJobHistory.sh does not work in that case.
cat Test.txt | while read line; do autosys_showJobHistory.sh $line | grep 1[1..6]:[0..9][0..9] | grep 24.12.2012 | tail -1 ; done
What I am doing wrong in the second command ?

Wrote all of below, and then noticed your grep statement.
Recall that ksh doesn't support .. as an indicator for 'expand this range of values'. (I assume that's your intent). It's also made ambiguous by your lack of quoting arguments to grep. If you were using syntax that the shell would convert, then you wouldn't really know what reg-exp is being sent to grep. Always better to quote argments, unless you know for sure that you need the unquoted values. Try rewriting as
grep '1[1-6]:[0-9][0-9]' | grep '24.12.2012'
Also, are you deliberately using the 'match any char' operator '.' OR do you want to only match a period char? If you want to only match a period, then you need to escape it like \..
Finally, if any of your files you're processing have been created on a windows machine and then transfered to Unix/Linux, very likely that the line endings (Ctrl-MCtrl-J) (\r\n) are causing you problems. Cleanup your PC based files (or anything that was sent via ftp) with dos2unix file [file2 ...].
If the above doesn't help, You'll have to "divide and conquer" to debug your problem.
When I did the following tests, I got the expected output
$ echo "var1" | while read line ; do print "line=${line}" ; done
line=var1
$ vi Test.txt
$ cat Test.txt
var1
$ cat Test.txt | while read line ; do print "line=${line}" ; done
line=var1
Unrelated to your question, but certain to cause comment is your use of the cat commnad in this context, which will bring you the UUOC award. That can be rewritten as
while read line ; do print "line=${line}" ; done < Test.txt
But to solve your problem, now turn on the shell debugging/trace options, either by changing the top line of the script (the shebang line) like
#!/bin/ksh -vx
Or by using a matched pair to track the status on just these lines, i.e.
set -vx
while read line; do
print -u2 -- "#dbg: Line=${line}XX"
autosys_showJobHistory.sh $line \
| grep 1[1..6]:[0..9][0..9] \
| grep 24.12.2012 \
| tail -1
done < Test.txt
set +vx
I've added an extra debug step, the print -u2 -- .... (u2=stderror, -- closes option processing for print)
Now you can make sure no extra space or tab chars are creeping in, by looking at that output.
They shouldn't matter, as you have left your $line unquoted. As part of your testing, I'd recommend quoting it like "${line}".
Then I'd comment out the tail and the grep lines. You want to see what step is causing this to break, right? So does the autosys_script by itself still produce the intermediate output you're expecting? Then does autosys + 1 grep produce out as expected, +2 greps, + tail? You should be able to easily see where you're loosing your output.
IHTH

Related

Why does "cut" command skip first line in this "while read line" loop?

I'm writing a bash script, and I need to take the second field of every line in a file, and save them in another file. I know there are many possible ways to do this, BUT, I tried first using while read line; do, and I got stuck. Now, I really want to know what is happening.
For example, input file would be:
line1 11111
line2 222222
line3 333
line4 4444
(The field separtor is "\t").
This is what I was doing:
inputfile=$1
cat $"inputfile" | while read -r line
do
cut -f2 >> results_file
done
The problem is, the output would be:
222222
333
4444
(skipping the first line)
I´ve alredy tested hundreds of modifications, and tried to used other commands instead of cut(like, sed, grep...). I would appreciate some help, or someone pointing me in the right direction.
Thank you very much!
You are not using the variable $line set by read. Try instead
inputfile=$1
cat "$inputfile" | while read -r line
do
echo "$line" | cut -f2 >> results_file
done
In your original code, the while loop is actually run only once, not four times; try putting echo 'Hello!' in the loop to your original code. You would see the message only once, not four times. I guess, without echo "$line" | part, cut -f2 ... part consumes the pipe away.
That is, your while loop first consumes the first line of the stdin and puts this line in the variable $line, leaving the next three lines for later use. But $line is never used. Instead, the remaining three lines are consumed by the command cut.
All commands within a command group are within the scope of any redirections applied to a command group (or any compound command):
— https://mywiki.wooledge.org/BashGuide/CompoundCommands
The pipe operator creates a subshell environment for each command.
— https://mywiki.wooledge.org/BashGuide/InputAndOutput
We can interpret the quotes as "the stdin to your while loop (i.e., the output of cat "$inputfile") is accessed by cut, unless you sever its access by creating a new subshell e.g., by another pipe echo "$line" | ...."
By the way, you can just use cut -f2 "$inputfile" >> results_file without the while loop.
With respect to your comment Does it mean to use "\t at the end" as a separator - no. You're confusing what was suggested, $'\t' with '\t$'. $'\t' means "the literal tab character generated from the escape sequence \t".
You also said in your comment your real 2nd fields are URLs to be curled. You shouldn't be using a UUOC and cut anyway, here's how to really do this:
while IFS=$'\t' read -r key url; do
val=$(curl "$url" | whatever)
printf '%s\t%s\n' "$key" "$val"
done < "$inputfile" > results_file
Replace whatever with whatever command you use to produce the output you want from the curl output.

sed - unterminated `s' command

I have this peace of code:
cat BP.csv | while read line ; do
goterm=$(awk '{print $1}') ;
name=$(awk '{print $2}') ;
grep -w "$goterm" GOEA.csv | sed "s/$goterm/pi/g" ;
done
file BP.csv has this format:
GO:0008283 cell proliferation
GO:0009405 pathogenesis
GO:0010201 response to continuous far red light stimulus by the high-irradiance response system
GO:0009641 shade avoidance
while GOEA.csv has this format:
4577 GO:0006807 0.994 2014_06_01
4577 GO:0016788 0.989 2014_06_01
4577 GO:0043169 0.977 2014_06_01
4577 GO:0043170 0.963 2014_06_01
sed doesn't work. I want to change GO:0043170 for example, to string "pi", but it gives:
sed: -e expression #1, char 12: unterminated `s' command
Why?
Thanks.
You running your awk command against no input, Try this:
cat BP.csv | while read line ; do
goterm=$(awk '{print $1}' <<< "$line") ;
name=$(awk '{print $2}' <<< "$line" ) ;
grep -w "$goterm" GOEA.csv | sed "s/$goterm/pi/g" ;
done
Let's clean up this code a bit:
while read goterm name
do
grep -w "$goterm" GOEA.csv | sed "s/$goterm/pi/g"
done < BP.cvs
The problem is that your awk statements are attempting to read in from STDIN just like your while is doing. You're reading from the same input stream.
What you want to do is to pull out the values from your line. I'm using read to do this. The read statement uses the values in $IFS to separate out the input. This is normally spaces, tabs, and newlines. The read reads each variable you put on the line, and the last value read in contains the entire rest of the line.
Thus:
while read line
reads in the entire line while:
while goterm name
will break the line as
goterm="GO:0008283"
name="cell proliferation"
One more thing. When you use grep and sed together, you probably can get away with just sed:
while read goterm name
do
sed -n "/$goterm/s/$goterm/pi/gp" GOEA.csv
done < BP.csv
The format for the sed command is:
/lines/command/parameters/
So, I'm searching for lines with $goterm in them, then I am replacing $goterm with pi. The -n means don't print out the lines as sed processes them and p means to print out the lines were the substitute is located.
By the way, csv as a file suffix means comma separated values but neither file looks like it is comma separated. Are these tabs separating each field. If so, you'll need to modify $IFS to be tabs.
I would restructure that whole thing more like this:
while read goterm restofline
do
grep -w "${goterm}" GOEA.csv | sed -e "s/${goterm}/pi/g"
done < BP.csv
No reason for the awk things, as the bash read builtin will do rudimentary field splitting for you if you give it multiple variables. Also, you aren't using name anyway, so it's not needed. cat is unnecessary as well.
Depending on your exact use case, even the grep may be unnecessary, making the inner command simply sed -ne "s/${goterm}/pi/gp" GOEA.csv. Unless your purpose for the grep -w is eliminating lines where ${goterm} is a substring of a word instead of the whole word...
For future reference, inserting a set -x above your loop in your script would show you the exact commands that are being run, so that you can compare them with your expectations.

Passing input to sed, and sed info to a string

I have a list of files (~1000) and there is 1 file per line in my text file named: 'files.txt'
I have a macro that looks something like the following:
#!/bin/sh
b=$(sed '${1}q;d' files.txt)
cat > MyMacro_${1}.C << +EOF
myFile = new TFile("/MYPATHNAME/$b");
+EOF
and I use this input script by doing
./MakeMacro.sh 1
and later I want to do
./MakeMacro.sh 2
./MakeMacro.sh 3
...etc
So that it reads the n'th line of my files.txt and feeds that string to my created .C macro.
So that it reads the n'th line of my files.txt and feeds that string to my created .C macro.
Given this statement and your tags, I'm going to answer using shell tools and not really address the issue of the .c macro.
The first line of your script contains a sed script. There are numerous ways to get the Nth line from a text file. The simplest might be to use head and tail.
$ head -n "${i}" files.txt | tail -n 1
This takes the first $i lines of files.txt, and shows you the last 1 lines of that set.
$ sed -ne "${i}p" files.txt
This use of sed uses -n to avoid printing by default, then prints the $ith line. For better performance, try:
$ sed -ne "${i}{p;q;}" files.txt
This does the same, but quits after printing the line, so that sed doesn't bother traversing the rest of the file.
$ awk -v i="$i" 'NR==i' files.txt
This passes the shell variable $i into awk, then evaluates an expression that tests whether the number of records processed is the same as that variable. If the expression evaluates true, awk prints the line. For better performance, try:
$ awk -v i="$i" 'NR==i{print;exit}' files.txt
Like the second sed script above, this will quit after printing the line, so as to avoid traversing the rest of the file.
Plenty of ways you could do this by loading the file into an array as well, but those ways would take more memory and perform less well. I'd use one-liners if you can. :)
To take any of these one-liners and put it into your script, you already have the notation:
if expr "$i" : '[0-9][0-9]*$' >/dev/null; then
b=$(sed -ne "${i}{p;q;}" files.txt)
else
echo "ERROR: invalid line number" >&2; exit 1
fi
If I am understanding you correctly, you can do a for loop in bash to call the script multiple times with different arguments.
for i in `seq 1 n`; do ./MakeMacro.sh $i; done
Based on the OP's comment, it seems that he wants to submit the generated files to Condor. You can modify the loop above to include the condor submission.
for i in `seq 1 n`; do ./MakeMacro.sh $i; condor_submit <OutputFile> ; done
i=0
while read file
do
((i++))
cat > MyMacro_${i}.C <<-'EOF'
myFile = new TFile("$file");
EOF
done < files.txt
Beware: you need tab indents on the EOF line.
I'm puzzled about why this is the way you want to do the job. You could have your C++ code read files.txt at runtime and it would likely be more efficient in most ways.
If you want to get the Nth line of files.txt into MyMacro_N.C, then:
{
echo
sed -n -e "${1}{s/.*/myFile = new TFILE(\"&\");/p;q;}" files.txt
echo
} > MyMacro_${1}.C
Good grief. The entire script should just be (untested):
awk -v nr="$1" 'NR==nr{printf "\nmyFile = new TFile(\"/MYPATHNAME/%s\");\n\n",$0 > ("MyMacro_"nr".C")}' files.txt
You can throw in a ;exit before the } if performance is an issue but I doubt if it will be.

bash script prepending ? to file name

I am using the below script. When I have it echo $f as shown below, it gives the correct result:
#/bin/bash
var="\/home\/"
while read p; do
f=$(echo $p | sed "s/${var}/\\n/g")
f=${f%.sliced.bam}.fastq
echo $f
~/bin/samtools view $p | awk '{print "#"$1"\n"$10"\n+\n"$11}' > $f
./run.sh $f ${f%.fastq}
rm ${f%.sliced.bam}.fastq
done < $1
I get the output as expected
test.fastq
But the file being created by awk > $f has the name
?test.fastq
Note that the overall goal here is to run this loop on every file listed in a file with absolute paths but then write locally (which is what the sed call is for)
edit: Run directly on the command line (without variables) the samtools | awk line runs correctly.
Awk cannot possibly have anything to do with your problem. The shell is completely responsible for file redirection, so f MUST have a weird character in it.
Most likely whatever you are sending to this script has a special character in it (e.g. perhaps a UTF character, and your terminal is showing ASCII only). When you do the echo, the shell doesn't know how to display the char, and probably just shows it as whitespace, and when you send it through ls (which might be doing things like colorization) it combines in a strange way and ends up showing the ?.
Oh wait...why are you putting a newline into the filename with sed??? That is possibly your problem...try just:
sed "s/${var}//g"

how to proceed once a file containing something in shell

I am writing some BASH shell script that will continuously check a file to see if the file already contains "Completed!" before proceeding. (Of course, assume the file is being updated and will eventually contain the phrase "Completed!")
I am not sure how to do this. Thank you for your help.
You can do something like:
while ! grep -q -e 'Completed!' file ; do
sleep 1 # Or some other number of seconds
done
# Here the file contains completed
Amongst the standard utilities, tail has an option to keep reading from a file: tail -f. So filter the output of tail -f.
<some_file tail -f -n +1 | grep 'Completed!' | head -n 1 >/dev/null
There may be a delay due to buffering. You can at least reduce the delay by using fewer tools in the pipeline. In fact, some implementations of tail never buffer when you do tail -f, so the following snippet will return as soon as Completed! is written to the file.
<some_file tail -f -n +1 | sed -e '/Completed!/ q'
This assumes that the file is being appended to by some other tool. If the file is overwritten by the data-producing program after you start tail, this solution won't work. You can search the file periodically. On some systems you can call a notification mechanism to know whenever the file changes, e.g. with inotifywait under Linux.
I've done this in Kornshell:
tail -f somefile | while read line
do
echo $line
[[ $line == *Completed!* ]] && break
done
Note no quotes around the *Completed!* string. This allows the double square brackets to do glob pattern matching instead of string matching.
This seems to work in BASH too. However, the line with the Completed must end in a NL. Otherwise, it'll take an extra line before it breaks the loop.
You can use grep too:
tail -f somefile | while read line
do
echo $line
grep -iq "Completed!" && break
done
The -q parameter means quiet. If your grep doesn't take the -q parameter, you might have to pipe it to /dev/null. The -i is ignore case. Whether you want to do that is up to you.
The advantage is that you aren't doing any processing unless there's a line to read. Using sleep may mean you miss the line, or that you're processing when no line has been added to the file.
Using grep in a pipe you may turn on line buffering mode by adding the --line-buffered option!

Resources