I write a bash script that ask user to input file in full path:
printf ' Please type the path of ISO file:\n'
read -p ' ' berkas
if [[ -f $berkas ]]
then
printf " $berkas found\n"
else
printf " Could not find $berkas\n"
fi
But it failed if file path is single quoted (e.g if i drag file from Nautilus window to script windows):
Please type the path of ISO file:
'/home/iza/Software/Windows/ISO/Windows7_Ultimate_x64_SP1.iso'
Could not find '/home/iza/Software/Windows/ISO/Windows7_Ultimate_x64_SP1.iso'
What's wrong with the code? I would love if workaround is not involving sed or awk.
Thanx :)
You can remove the quotes from the start and end of the variable in bash using:
berkas=${berkas%\'} # remove single quote from end of variable if it exists
berkas=${berkas#\'} # remove single quote from start of variable if it exists
If no quotes are present, nothing will be removed.
It's generally considered good practice to put double quotes around your variables, for example
[[ -f "$berkas" ]]
Also, rather than using printf and appending a \n newline character manually, you can just use echo:
echo ' Please type the path of ISO file:'
read -r -p ' ' berkas
if [[ "$berkas" = \'*\' ]]; then
berkas=${berkas%\'}
berkas=${berkas#\'}
fi
if [[ -f "$berkas" ]]
then
echo " $berkas found"
else
echo " Could not find $berkas"
fi
As suggested in the comments (thanks Etan), I have added a check that the variable starts and ends with a single quote, which makes the script slightly safer. I also added the -r switch to read, which you almost always want to use.
disclaimer
It is worth mentioning that this approach indiscriminately removes quotes from the start and/or end of the variable, so if it possible that your filenames legitimately may contain quotes in those positions, this will not work.
Related
I was looking for the best way to find iterate over files in a variables path and came across this question.
However, this and every other solution I've found uses a literal path rather than a variable, and I believe this is my problem.
for file in "${path}/*"
do
echo "INFO - Checking $file"
[[ -e "$file" ]] || continue
done
Even though there are definitely files in the directory (and if i put one of the literal paths in place of ${path} I get the expected result), this always only iterates once, and the value of $file is always the literal value of ${path}/* without any globbing.
What am I doing wrong?
Glob expansion doesn't happen inside quotes (both single and double) in shell.
You should be using this code:
for file in "$path"/*; do
echo "INFO - Checking $file"
[[ -e $file ]] || continue
done
I am working on a script and I need to compare a filename to another one and look for specific changes (in this case a "(x)" added to a filename when OS X needs to add a file to a directory, when a filename already exists) so this is an excerpt of the script, modified to be tested without the rest of it.
#!/bin/bash
p2_s2="/Path/to file (name)/containing - many.special chars.docx.gdoc"
next_line="/Path/to file (name)/containing - many.special chars.docx (1).gdoc"
file_ext=$(echo "${p2_s2}" | rev | cut -d '.' -f 1 | rev)
file_name=$(basename "${p2_s2}" ".${file_ext}")
file_dir=$(dirname "${p2_s2}")
esc_file_name=$(printf '%q' "${file_name}")
esc_file_dir=$(printf '%q' "${file_dir}")
esc_next_line=$(printf '%q' "${next_line}")
if [[ ${esc_next_line} =~ ${esc_file_dir}/${esc_file_name}\ \(?\).${file_ext} ]]
then
echo "It's a duplicate!"
fi
What I'm trying to do here is detect if the file next_line is a duplicate of p2_s2. As I am expecting multiple duplicates, next_line can have a (1) appended at the end of a filename or any other number in brackets (Although I am sure no double digits). As I can't do a simple string compare with a wildcard in the middle, I tried using the "=~" operator and escaping all the special chars. Any idea what I'm doing wrong?
You can trim ps2_s2's extension, trim next_line's extension including the number inside the parenthesis and see if you get the same file name. If you do - it's a duplicate. In order to do so, [[ allows us to perform a comparison between a string and a Glob.
I used extglob's +( ... ) pattern, so I can use +([0-9]) to match the number inside the parenthesis. Notice that extglob is enabled by shopt -s extglob.
#!/bin/bash
p2_s2="/Path/to/ps2.docx.gdoc"
next_line="/Path/to/ps2(1).docx.gdoc"
shopt -s extglob
if [[ "${p2_s2%%.*}" = "${next_line%%\(+([0-9])\).*}" ]]; then
printf '%s is a duplicate of %s\n' "$next_line" "$p2_s2"
fi
EDIT:
I now see that you've edited your question, so in case this solution is not enough, I'm positive that it'll be a good template to work with.
The (1) in next_line doesn't come before the final . it comes before the second to final . in the original filename but you only strip off a single . as the extension.
So when you generate the comparison filename you end up with /Path/to\ file\ \(name\)/containing\ -\ many.special\ chars.docx\ \(?\).gdoc which doesn't match what you expect.
If you had added set -x to the top of your script you'd have seen what the shell was actually doing and seen this.
What does OS X actually do in this situation? Does it add (#) before .gdoc? Does it add it before.docx`? Does it depend on whether OS X knows what the filename is (it is some type it can open natively)?
I have some file in the name of OBS_SURFACE1**, OBS_SURFACE101, OBS_SURFACE103. Yes, there indeed is a file named OBS_SURFACE1**, which I guess where the problem arise. I wrote a bash script which has:
for fil in ` ls OBS_DOMAIN1?? `
do
echo "appending" $fil
done
The first value of fil will be OBS_SURFACE1** OBS_SURFACE101 OBS_SURFACE103, the second OBS_SURFACE101. While I expect the first to be OBS_SURFACE1**. If there is no OBS_SURFACE1** file, there would be no problem. Why is that then?
Don't parse ls! It will only ever lead to problems. Use a glob instead:
for fil in OBS_DOMAIN1??
do
echo "appending $fil"
done
The problem that you are experiencing stems from the fact that the output of ls contains *, which are being expanded by bash. Note that I have also quoted the whole string to be echoed, which protects against word splitting inside the loop. See the links provided in the comments above for more details on that.
As pointed out in the comments (thanks Charles), you may also want to enable nullglob before your loop like this: shopt -s nullglob. This will mean that if there are no files that match the pattern, the loop will not run at all, rather than running once with $fil taking the literal value OBS_DOMAIN1??. Another option would be to check whether the file exists in within the loop, for example using:
if [[ -e "$fil" ]]; then
echo "appending $fil"
fi
or the more compact [[ -e "$fil" ]] && echo "appending $fil".
yet another way of doing this :
echo appending OBS_DOMAIN1??
this will list all files , no loop needed.
I am looking to search for strings within a file using variables.
I have a script that will accept 3 or 4 parameters: 3 are required; the 4th isn't mandatory.
I would like to search the text file for the 3 parameters matching within the same line, and if they do match then I want to remove that line and replace it with my new one - basically it would update the 4th parameter if set, and avoid duplicate entries.
Currently this is what I have:
input=$(egrep -e '$domain\s+$type\s+$item' ~/etc/security/limits.conf)
if [ "$input" == "" ]; then
echo $domain $type $item $value >>~/etc/security/limits.conf
echo \"$domain\" \"$type\" \"$item\" \"$value\" has been successfully added to your limits.conf file.
else
cat ~/etc/security/limits.conf | egrep -v "$domain|$type|$item" >~/etc/security/limits.conf1
rm -rf ~/etc/security/limits.conf
mv ~/etc/security/limits.conf1 ~/etc/security/limits.conf
echo $domain $type $item $value >>~/etc/security/limits.conf
echo \"$domain\" \"$type\" \"$item\" \"$value\" has been successfully added to your limits.conf file.
exit 0
fi
Now I already know that the input=egrep etc.. will not work; it works if I hard code some values, but it won't accept those variables. Basically I have domain=$1, type=$2 and so on.
I would like it so that if all 3 variables are not matched within one line, than it will just append the parameters to the end of the file, but if the parameters do match, then I want them to be deleted, and appended to the file. I know I can use other things like sed and awk, but I have yet to learn them.
This is for a school assignment, and all help is very much appreciated, but I'd also like to learn why and how it works/doesn't, so if you can provide answers to that as well that would be great!
Three things:
To assign the output of a command, use var=$(cmd).
Don't put spaces around the = in assignments.
Expressions don't expand in single quotes: use double quotes.
To summarize:
input=$(egrep -e "$domain\s+$type\s+$item" ~/etc/security/limits.conf)
Also note that ~ is your home directory, so if you meant /etc/security/limits.conf and not /home/youruser/etc/security/limits.conf, leave off the ~
You have several bugs in your script. Here's your script with some comments added
input=$(egrep -e '$domain\s+$type\s+$item' ~/etc/security/limits.conf)
# use " not ' in the string above or the shell can't expand your variables.
# some versions of egrep won't understand '\s'. The safer, POSIX character class is [[:blank:]].
if [ "$input" == "" ]; then
# the shell equality test operator is =, not ==. Some shells will also take == but don't count on it.
# the normal way to check for a variable being empty in shell is with `-z`
# you can have problems with tests in some shells if $input is empty, in which case you'd use [ "X$input" = "X" ].
echo $domain $type $item $value >>~/etc/security/limits.conf
# echo is unsafe and non-portable, you should use printf instead.
# the above calls echo with 4 args, one for each variable - you probably don't want that and should have double-quoted the whole thing.
# always double-quote your shell variables to avoid word splitting ad file name expansion (google those - you don't want them happening here!)
echo \"$domain\" \"$type\" \"$item\" \"$value\" has been successfully added to your limits.conf file.
# the correct form would be:
# printf '"%s" "%s" "%s" "%s" has been successfully added to your limits.conf file.\n' "$domain" "$type" "$item" "$value"
else
cat ~/etc/security/limits.conf | egrep -v "$domain|$type|$item" >~/etc/security/limits.conf1
# Useless Use Of Cat (UUOC - google it). [e]grep can open files just as easily as cat can.
rm -rf ~/etc/security/limits.conf
# -r is for recursively removing files in a directory - inappropriate and misleading when used on a single file.
mv ~/etc/security/limits.conf1 ~/etc/security/limits.conf
# pointless to remove the file above when you're overwriting it here anyway
# If your egrep above failed to create your temp file (e.g. due to memory or permissions issues) then the "mv" above would zap your real file. the correct way to do this is:
# egrep regexp file > tmp && mv tmp file
# i.e. use && to only do the mv if creating the tmp file succeeded.
echo $domain $type $item $value >>~/etc/security/limits.conf
# see previous echo comments.
echo \"$domain\" \"$type\" \"$item\" \"$value\" has been successfully added to your limits.conf file.
# ditto
exit 0
# pointless and misleading having an explicit "exit <success>" when that's what the script will do by default anyway.
fi
This line:
input=$(egrep -e '$domain\s+$type\s+$item' ~/etc/security/limits.conf)
requires double quotes around the regex to allow the shell to interpolate the variable values.
input=$(egrep -e "$domain\s+$type\s+$item" ~/etc/security/limits.conf)
You need to be careful with backslashes; you probably don't have to double them up in this context, but you should be sure you know why.
You should be aware that your first egrep commands is much more restrictive in what it selects than the second egrep which is used to delete data from the file. The first requires the entry with the three fields in the single line; the second only requires a match with any one of the words (and that could be part of a larger word) to delete the line.
Since ~/etc/security/limits.conf is a file, there is no need to use the -r option of rm; it is advisable not to use the -r unless you intend to remove directories.
I am writing a simple shell script to make automated backups, and I am trying to use basename to create a list of directories and them parse this list to get the first and the last directory from the list.
The problem is: when I use basename in the terminal, all goes fine and it gives me the list exactly as I want it. For example:
basename -a /var/*/
gives me a list of all the directories inside /var without the / in the end of the name, one per line.
BUT, when I use it inside a script and pass a variable to basename, it puts single quotes around the variable:
while read line; do
dir_name=$(echo $line)
basename -a $dir_name/*/ > dir_list.tmp
done < file_with_list.txt
When running with +x:
+ basename -a '/Volumes/OUTROS/backup/test/*/'
and, therefore, the result is not what I need.
Now, I know there must be a thousand ways to go around the basename problem, but then I'd learn nothing, right? ;)
How to get rid of the single quotes?
And if my directory name has spaces in it?
If your directory name could include spaces, you need to quote the value of dir_name (which is a good idea for any variable expansion, whether you expect spaces or not).
while read line; do
dir_name=$line
basename -a "$dir_name"/*/ > dir_list.tmp
done < file_with_list.txt
(As jordanm points out, you don't need to quote the RHS of a variable assignment.)
Assuming your goal is to populate dir_list.tmp with a list of directories found under each directory listed in file_with_list.txt, this might do.
#!/bin/bash
inputfile=file_with_list.txt
outputfile=dir_list.tmp
rm -f "$outputfile" # the -f makes rm fail silently if file does not exist
while read line; do
# basic syntax checking
if [[ ! ${line} =~ ^/[a-z][a-z0-9/-]*$ ]]; then
continue
fi
# collect targets using globbing
for target in "$line"/*; do
if [[ -d "$target" ]]; then
printf "%s\n" "$target" >> $outputfile
fi
done
done < $inputfile
As you develop whatever tool will process your dir_list.tmp file, be careful of special characters (including spaces) in that file.
Note that I'm using printf instead of echo so that targets whose first character is a hyphen won't cause errors.
This might work
while read; do
find "$REPLY" >> dir_list.tmp
done < file_with_list.txt