Background
I'm looking to strip any # TODO comments from some python source code files output by git archive before sending it off. I'm looking to do so from a script that will be run from a variety of *nix OSes, so it should be as POSIX-compliant as possible.
I'm aware that find -print0 and xargs -0 aren't in the base spec, but they appear to be common enough that I'm fine with using them (unless a better alternative exists). I'm using ed due to sed -i not being in the base spec for in-place editing. Assume the command below is being run from the directory of an already un-tar'd git archive.
I'd be happy with an overall alternative solution for stripping the # TODO comments out, but to satisfy my curiosity I'd also like an answer to the particular problem I'm facing with the command I've come up with.
Existing Code
find . -type f -name "*.py" -print0 | xargs -0 -I {} ed -s {} << 'EOF'
,g/^[ \t]*#[ \t]*TODO/d
,s/[ \t]*#[ \t]*TODO//
w
EOF
Expected Result
All files ending in ".py" are stripped of full lines that only contain TODO comments, or end-of-line comments starting with TODO.
Actual Result
(stdout)
,g/^[ \t]*#[ \t]*TODO/d
,s/[ \t]*#[ \t]*TODO//
w
: No such file or directory
Current Theory
I believe that the << 'EOF' heredoc is being applied to xargs instead of ed, and I'm not sure how to fix that.
Fixing the << 'EOF' heredoc direction would take some sh -c trickery that ended up causing even more problems, so I tried re-approaching the problem without requiring heredocs at all.
I ended up landing on:
inline() {
# Ensure a file was provided
in="${1?No input file specified}"
# Create a temp file location
tmp="$(mktemp /tmp/tmp.XXXXXXXXXX)"
# Preserve the original file's permissions
cp -p "$in" "$tmp"
# Make $# be the original command
shift
# Send original file contents to stdin, output to temp file
"$#" < "$in" > "$tmp"
# Move modified temp file to original location, with permissions and all
mv -f "$tmp" "$in"
}
find . -type f -name "*.py" -exec grep -ilE '#[ \t]*TODO' {} \+ | while read file; do
inline "$file" sed -e '/^[ \t]*#[ \t]*TODO/ d' -e 's/[ \t]*#[ \t]*TODO//'
done
mktemp isn't technically in the base spec, but appears to be fairly portable so I'm fine including it. ed was also causing me some problems, so I went back to sed with a custom function to replicate the unavailable -i flag for in-place operations.
Related
First off, I'd like to say that I know this is almost an exact duplicate of some posts that I've read, but have not had any luck with referencing.
I have 100+ files that all follow a very strict naming convention of 5_##_<name>.ext My issue was that when originally making these files I failed to realise that 5_100_ and above would mess up my ordering.
I am now trying to append a 0 in front of every number between 01 and 99. I've written a bash script using sed that works for the file contents (the file name is in the file as well):
#!/bin/bash
for fl in *.tcl; do
echo Filename: $fl
#sed -i 's/5_\(..\)_/5_0\1_/g' $fl
done
However, this only changes the contents and not the filename itself. I've read that mv is the solution (rename is simpler but I do not have it on my system). My current incarnation of my multiple attempts is:
mv "$fl" $(echo "$file" | sed -e 's/5_\(..\)_/5_0\1_/g') but it gives me an error: mv: missing destination file operand after <filename>
Again, I'm sorry about the duplicate but I wasn't able to solve my issue by reading it. I'm sure I'm just using the combination of mv and sed incorrectly.
Solution was entered in the comments. I was using $file instead of $fl.
Something like this might be useful:
for n in $(seq 99)
do
prefix2="5_$(printf "%02d" ${n})_"
prefix3="5_$(printf "%03d" ${n})_"
for f in ${prefix2}*.tcl
do
suffix="${f#${prefix2}}"
[[ -r "${prefix3}${suffix}" ]] || mv "${prefix2}${suffix}" "${prefix3}${suffix}"
done
done
Rather than processing every single file, it only looks at the ones that currently have a "5_XX_" prefix, and only renames them if the corresponding "5_XXX_" file doesn't already exist...
#!/bin/bash
for fl in *.tcl
do
NewName="$(echo "${fl} | sed '/^5_[0-9]\{2\}_/ s/../&0/' )"
#echo "Filename: ${fl} -> ${NewName}
[ ! "${fl}" = "${NewName}" ] && mv ${fl} ${NewName}
done
With a bit a securisation a allow to pass several time on same folder (changing only needed one).
Under linux (non posix sed by default), use sed --posix instead of simple sed call
The following command is correctly changing the contents of 2 files.
sed -i 's/abc/xyz/g' xaa1 xab1
But what I need to do is to change several such files dynamically and I do not know the file names. I want to write a command that will read all the files from current directory starting with xa* and sed should change the file contents.
I'm surprised nobody has mentioned the -exec argument to find, which is intended for this type of use-case, although it will start a process for each matching file name:
find . -type f -name 'xa*' -exec sed -i 's/asd/dsg/g' {} \;
Alternatively, one could use xargs, which will invoke fewer processes:
find . -type f -name 'xa*' | xargs sed -i 's/asd/dsg/g'
Or more simply use the + exec variant instead of ; in find to allow find to provide more than one file per subprocess call:
find . -type f -name 'xa*' -exec sed -i 's/asd/dsg/g' {} +
Better yet:
for i in xa*; do
sed -i 's/asd/dfg/g' $i
done
because nobody knows how many files are there, and it's easy to break command line limits.
Here's what happens when there are too many files:
# grep -c aaa *
-bash: /bin/grep: Argument list too long
# for i in *; do grep -c aaa $i; done
0
... (output skipped)
#
You could use grep and sed together. This allows you to search subdirectories recursively.
Linux: grep -r -l <old> * | xargs sed -i 's/<old>/<new>/g'
OS X: grep -r -l <old> * | xargs sed -i '' 's/<old>/<new>/g'
For grep:
-r recursively searches subdirectories
-l prints file names that contain matches
For sed:
-i extension (Note: An argument needs to be provided on OS X)
Those commands won't work in the default sed that comes with Mac OS X.
From man 1 sed:
-i extension
Edit files in-place, saving backups with the specified
extension. If a zero-length extension is given, no backup
will be saved. It is not recommended to give a zero-length
extension when in-place editing files, as you risk corruption
or partial content in situations where disk space is exhausted, etc.
Tried
sed -i '.bak' 's/old/new/g' logfile*
and
for i in logfile*; do sed -i '.bak' 's/old/new/g' $i; done
Both work fine.
#PaulR posted this as a comment, but people should view it as an answer (and this answer works best for my needs):
sed -i 's/abc/xyz/g' xa*
This will work for a moderate amount of files, probably on the order of tens, but probably not on the order of millions.
Another more versatile way is to use find:
sed -i 's/asd/dsg/g' $(find . -type f -name 'xa*')
I'm using find for similar task. It is quite simple: you have to pass it as an argument for sed like this:
sed -i 's/EXPRESSION/REPLACEMENT/g' `find -name "FILE.REGEX"`
This way you don't have to write complex loops, and it is simple to see, which files you are going to change, just run find before you run sed.
u can make
'xxxx' text u search and will replace it with 'yyyy'
grep -Rn '**xxxx**' /path | awk -F: '{print $1}' | xargs sed -i 's/**xxxx**/**yyyy**/'
There's some good answers above. I thought I'd throw in one more that is succinct and parallelizable, using GNU parallel, which I often prefer to xargs:
parallel sed -i 's/abc/xyz/g' {} ::: xa*
Combine this with the -j N option to run N jobs in parallel.
If you are able to run a script, here is what I did for a similar situation:
Using a dictionary/hashMap (associative array) and variables for the sed command, we can loop through the array to replace several strings. Including a wildcard in the name_pattern will allow to replace in-place in files with a pattern (this could be something like name_pattern='File*.txt' ) in a specific directory (source_dir).
All the changes are written in the logfile in the destin_dir
#!/bin/bash
source_dir=source_path
destin_dir=destin_path
logfile='sedOutput.txt'
name_pattern='File.txt'
echo "--Begin $(date)--" | tee -a $destin_dir/$logfile
echo "Source_DIR=$source_dir destin_DIR=$destin_dir "
declare -A pairs=(
['WHAT1']='FOR1'
['OTHER_string_to replace']='string replaced'
)
for i in "${!pairs[#]}"; do
j=${pairs[$i]}
echo "[$i]=$j"
replace_what=$i
replace_for=$j
echo " "
echo "Replace: $replace_what for: $replace_for"
find $source_dir -name $name_pattern | xargs sed -i "s/$replace_what/$replace_for/g"
find $source_dir -name $name_pattern | xargs -I{} grep -n "$replace_for" {} /dev/null | tee -a $destin_dir/$logfile
done
echo " "
echo "----End $(date)---" | tee -a $destin_dir/$logfile
First, the pairs array is declared, each pair is a replacement string, then WHAT1 will be replaced for FOR1 and OTHER_string_to replace will be replaced for string replaced in the file File.txt. In the loop the array is read, the first member of the pair is retrieved as replace_what=$i and the second as replace_for=$j. The find command searches in the directory the filename (that may contain a wildcard) and the sed -i command replaces in the same file(s) what was previously defined. Finally I added a grep redirected to the logfile to log the changes made in the file(s).
This worked for me in GNU Bash 4.3 sed 4.2.2 and based upon VasyaNovikov's answer for Loop over tuples in bash.
The Silver Searcher Solution
I'm adding another option for those people who don't know about the amazing tool called The Silver Searcher (command line tool is ag).
Note: You can use grep and other tools to do the same thing here, but The Silver Searcher is fantastic :)
TLDR
ag -l 'abc' | xargs sed -i 's/abc/xyz/g'
Install The Silver Searcher
sudo apt install silversearcher-ag # Debian / Ubuntu
sudo pacman -S the_silver_searcher # Arch / EndeavourOS
sudo yum install epel-release the_silver_searcher # RHEL / CentOS
Demo Files
Paste the following into your terminal to create some demonstration files:
mkdir /tmp/food
cd /tmp/food
content="Everybody loves to abc this food!"
echo "$content" > ./milk
echo "$content" > ./bread
mkdir ./fastfood
echo "$content" > ./fastfood/pizza
echo "$content" > ./fastfood/burger
mkdir ./fruit
echo "$content" > ./fruit/apple
echo "$content" > ./fruit/apricot
Using 'ag'
The following ag command will recursively find all the files that contain the string 'abc'. It ignores the .git directory, .gitignore files, and other ignore files:
$ ag 'abc'
milk
1:Everybody loves to abc this food!
bread
1:Everybody loves to abc this food!
fastfood/burger
1:Everybody loves to abc this food!
fastfood/pizza
1:Everybody loves to abc this food!
fruit/apple
1:Everybody loves to abc this food!
fruit/apricot
1:Everybody loves to abc this food!
To just list the files that contain the string 'abc', use the -l switch:
$ ag -l 'abc'
bread
fastfood/burger
fastfood/pizza
fruit/apricot
milk
fruit/apple
Changing Multiple Files
Finally, using xargs and sed, we can replace the 'abc' string with another string:
ag -l 'abc' | xargs sed -i 's/abc/eat/g'
In the above command, ag is listing all the files that contain the string 'abc'. The xargs command is splitting the file names and piping them individually into the sed command.
I'm trying to change the name of "my-silly-home-page-name.html" to "index.html" in all documents within a given master directory and subdirs.
I saw this: Shell script - search and replace text in multiple files using a list of strings.
And this: How to change all occurrences of a word in all files in a directory
I have tried this:
grep -r "my-silly-home-page-name.html" .
This finds the lines on which the text exists, but now I would like to substitute 'my-silly-home-page-name' for 'index'.
How would I do this with sed or perl?
Or do I even need sed/perl?
Something like:
grep -r "my-silly-home-page-name.html" . | sed 's/$1/'index'/g'
?
Also; I am trying this with perl, and I try the following:
perl -i -p -e 's/my-silly-home-page-name\.html/index\.html/g' *
This works, but I get an error when perl encounters directories, saying "Can't do inplace edit: SOMEDIR-NAME is not a regular file, <> line N"
Thanks,
jml
find . -type f -exec \
perl -i -pe's/my-silly-home-page-name(?=\.html)/index/g' {} +
Or if your find doesn't support -exec +,
find . -type f -print0 | xargs -0 \
perl -i -pe's/my-silly-home-page-name(?=\.html)/index/g'
Both pass to Perl as arguments as many names at a time as possible. Both work with any file name, including those that contains newlines.
If you are on Windows and you are using a Windows build of Perl (as opposed to a cygwin build), -i won't work unless you also do a backup of the original. Change -i to -i.bak. You can then go and delete the backups using
find . -type f -name '*.bak' -delete
This should do the job:
find . -type f -print0 | xargs -0 sed -e 's/my-silly-home-page-name\.html/index\.html/g' -i
Basically it gathers recursively all the files from the given directory (. in the example) with find and runs sed with the same substitution command as in the perl command in the question through xargs.
Regarding the question about sed vs. perl, I'd say that you should use the one you're more comfortable with since I don't expect huge differences (the substitution command is the same one after all).
There are probably better ways to do this but you can use:
find . -name oldname.html |perl -e 'map { s/[\r\n]//g; $old = $_; s/oldname.txt$/newname.html/; rename $old,$_ } <>';
Fyi, grep searches for a pattern; find searches for files.
I cannot get in-place editing Perl one-liners running under ActivePerl to work unless I specify them with a backup extension:
C:\> perl -i -ape "splice (#F, 2, 0, q(inserted text)); $_ = qq(#F\n);" file1.txt
Can't do inplace edit without backup.
The same command with -i.bak or -i.orig works a treat but creates an unwanted backup file in the process.
Is there a way around this?
This is a Windows/MS-DOS limitation. According to perldiag:
You're on a system such as MS-DOS that gets confused if you try reading from a deleted (but still opened) file. You have to say -i.bak, or some such.
Perl's -i implementation causes it to delete file1.txt while keeping an open handle to it, then re-create the file with the same name. This allows you to 'read' file1.txt even though it has been deleted and is being re-created. Unfortunately, Windows/MS-DOS does not allow you to delete a file that has an open handle attached to it, so this mechanism does not work.
Your best shot is to use -i.bak and then delete the backup file. This at least gives you some protection - for example, you could opt not to delete the backup if perl exits with a non-zero exit code. Something like:
perl -i.bak -ape "splice...." file1.txt && del file1.bak
Sample with recursive modify and delete both done by find. Works on e.g. mingw git bash on windows.
$ find . -name "*.xml" -print0 | xargs -0 perl -p -i.bak -e 's#\s*<property name="blah" value="false" />\s*##g'
$ find . -name "*.bak" -print0 | xargs -0 rm
Binary terminated values passed between find/xargs to handle spaces. Unusual s/ prefix to avoid mangling xml in search term. This assumes you didn't have any .bak files hanging around to begin.
I am interested into getting into bash scripting and would like to know how you can traverse a unix directory and log the path to the file you are currently looking at if it matches a regex criteria.
It would go like this:
Traverse a large unix directory path file/folder structure.
If the current file's contents contained a string that matched one or more regex expressions,
Then append the file's full path to a results text file.
Bash or Perl scripts are fine, although I would prefer how you would do this using a bash script with grep, awk, etc commands.
find . -type f -print0 | xargs -0 grep -l -E 'some_regexp' > /tmp/list.of.files
Important parts:
-type f makes the find list only files
-print0 prints the files separated not by \n but by \0 - it is here to make sure it will work in case you have files with spaces in their names
xargs -0 - splits input on \0, and passes each element as argument to the command you provided (grep in this example)
The cool thing with using xargs is, that if your directory contains really a lot of files, you can speed up the process by paralleling it:
find . -type f -print0 | xargs -0 -P 5 -L 100 grep -l -E 'some_regexp' > /tmp/list.of.files
This will run the grep command in 5 separate copies, each scanning another set of up to 100 files
use find and grep
find . -exec grep -l -e 'myregex' {} \; >> outfile.txt
-l on the grep gets just the file name
-e on the grep specifies a regex
{} places each file found by the find command on the end of the grep command
>> outfile.txt appends to the text file
grep -l -R <regex> <location> should do the job.
If you wanted to do this from within Perl, you can take the find commands that people suggested and turn them into a Perl script with find2perl:
If you have:
$ find ...
make that
$ find2perl ...
That outputs a Perl program that does the same thing. From there, if you need to do something that easy in Perl but hard in shell, you just extend the Perl program.
find /path -type f -name "*.txt" | awk '
{
while((getline line<$0)>0){
if(line ~ /pattern/){
print $0":"line
#do some other things here
}
}
}'
similar thread
find /path -type f -name "outfile.txt" | awk '
{
while((getline line<$0)>0){
if(line ~ /pattern/){
print $0":"line
}
}
}'