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I'm developing a pre-commit hook to avoid committing files with non-ascii chars, it works as well from unix system, using the below REGEX:
grep -P -n '[\x80-\xFF]' /tmp/app.txt
Now the issue that is giving me a lot of pain is that when i commit from windows, the result of the grep change, giving me a lot of char more than non ascii chars...
Does someone know how to fix this? I really try a lot of different things..
strings -n 1 filename will show the normal characters, but what if you only want to see the kind of file? file filename will show the kind of file but I am afraid it won't work for you.
You might try something like
cat /tmp/app.txt | tr -d "[:print:]\r\n" | wc -c
or avoiding the cat
tr -d "[:print:]\r\n" < /tmp/app.txt | wc -c
With the last update of our SuSE Enterprise Linux 11 (now bash 3.2.51(1)-release), the command "tail" seems to have lost its option to stream files:
tail: unrecognized option '--line-buffered'
Our tail is from "GNU coreutils 8.12, March 2013". Is there another, equivalent solution?
As far as can be told by simple googling, tail doesn't appear to have a --line-buffered option, grep does. --line-buffered is useful to force line buffering even when writing to a non-TTY, a typical idiom being:
tail -f FILE | grep --line-buffered REGEXP > output
Here the point of --line-buffered is to prevent grep from buffering output in 8K chunks and forcing the matched lines to immediately appear in the output file.
tail -f is unbuffered regardless of output type, so it doesn't need a --line-buffered option equivalent to the one in grep. This can be verified by running tail -f somefile | cat and appending a line to the file from another shell. One observes that, despite its standard output being a pipe, tail immediately flushes the newly arrived line.
For grep there's a fixed string option, -F (fgrep) to turn off regex interpretation of the search string.
Is there a similar facility for sed? I couldn't find anything in the man. A recommendation of another gnu/linux tool would also be fine.
I'm using sed for the find and replace functionality: sed -i "s/abc/def/g"
Do you have to use sed? If you're writing a bash script, you can do
#!/bin/bash
pattern='abc'
replace='def'
file=/path/to/file
tmpfile="${TMPDIR:-/tmp}/$( basename "$file" ).$$"
while read -r line
do
echo "${line//$pattern/$replace}"
done < "$file" > "$tmpfile" && mv "$tmpfile" "$file"
With an older Bourne shell (such as ksh88 or POSIX sh), you may not have that cool ${var/pattern/replace} structure, but you do have ${var#pattern} and ${var%pattern}, which can be used to split the string up and then reassemble it. If you need to do that, you're in for a lot more code - but it's really not too bad.
If you're not in a shell script already, you could pretty easily make the pattern, replace, and filename parameters and just call this. :)
PS: The ${TMPDIR:-/tmp} structure uses $TMPDIR if that's set in your environment, or uses /tmp if the variable isn't set. I like to stick the PID of the current process on the end of the filename in the hopes that it'll be slightly more unique. You should probably use mktemp or similar in the "real world", but this is ok for a quick example, and the mktemp binary isn't always available.
Option 1) Escape regexp characters. E.g. sed 's/\$0\.0/0/g' will replace all occurrences of $0.0 with 0.
Option 2) Use perl -p -e in conjunction with quotemeta. E.g. perl -p -e 's/\\./,/gi' will replace all occurrences of . with ,.
You can use option 2 in scripts like this:
SEARCH="C++"
REPLACE="C#"
cat $FILELIST | perl -p -e "s/\\Q$SEARCH\\E/$REPLACE/g" > $NEWLIST
If you're not opposed to Ruby or long lines, you could use this:
alias replace='ruby -e "File.write(ARGV[0], File.read(ARGV[0]).gsub(ARGV[1]) { ARGV[2] })"'
replace test3.txt abc def
This loads the whole file into memory, performs the replacements and saves it back to disk. Should probably not be used for massive files.
If you don't want to escape your string, you can reach your goal in 2 steps:
fgrep the line (getting the line number) you want to replace, and
afterwards use sed for replacing this line.
E.g.
#/bin/sh
PATTERN='foo*[)*abc' # we need it literal
LINENUMBER="$( fgrep -n "$PATTERN" "$FILE" | cut -d':' -f1 )"
NEWSTRING='my new string'
sed -i "${LINENUMBER}s/.*/$NEWSTRING/" "$FILE"
You can do this in two lines of bash code if you're OK with reading the whole file into memory. This is quite flexible -- the pattern and replacement can contain newlines to match across lines if needed. It also preserves any trailing newline or lack thereof, which a simple loop with read does not.
mapfile -d '' < file
printf '%s' "${MAPFILE//"$pat"/"$rep"}" > file
For completeness, if the file can contain null bytes (\0), we need to extend the above, and it becomes
mapfile -d '' < <(cat file; printf '\0')
last=${MAPFILE[-1]}; unset "MAPFILE[-1]"
printf '%s\0' "${MAPFILE[#]//"$pat"/"$rep"}" > file
printf '%s' "${last//"$pat"/"$rep"}" >> file
perl -i.orig -pse 'while (($i = index($_,$s)) >= 0) { substr($_,$i,length($s), $r)}'--\
-s='$_REQUEST['\'old\'']' -r='$_REQUEST['\'new\'']' sample.txt
-i.orig in-place modification with backup.
-p print lines from the input file by default
-s enable rudimentary parsing of command line arguments
-e run this script
index($_,$s) search for the $s string
substr($_,$i,length($s), $r) replace the string
while (($i = index($_,$s)) >= 0) repeat until
-- end of perl parameters
-s='$_REQUEST['\'old\'']', -r='$_REQUEST['\'new\'']' - set $s,$r
You still need to "escape" ' chars but the rest should be straight forward.
Note: this started as an answer to How to pass special character string to sed hence the $_REQUEST['old'] strings, however this question is a bit more appropriately formulated.
You should be using replace instead of sed.
From the man page:
The replace utility program changes strings in place in files or on the
standard input.
Invoke replace in one of the following ways:
shell> replace from to [from to] ... -- file_name [file_name] ...
shell> replace from to [from to] ... < file_name
from represents a string to look for and to represents its replacement.
There can be one or more pairs of strings.
I would like to generate a random filename in unix shell (say tcshell). The filename should consist of random 32 hex letters, e.g.:
c7fdfc8f409c548a10a0a89a791417c5
(to which I will add whatever is neccesary). The point is being able to do it only in shell without resorting to a program.
Assuming you are on a linux, the following should work:
cat /dev/urandom | tr -cd 'a-f0-9' | head -c 32
This is only pseudo-random if your system runs low on entropy, but is (on linux) guaranteed to terminate. If you require genuinely random data, cat /dev/random instead of /dev/urandom. This change will make your code block until enough entropy is available to produce truly random output, so it might slow down your code. For most uses, the output of /dev/urandom is sufficiently random.
If you on OS X or another BSD, you need to modify it to the following:
cat /dev/urandom | env LC_CTYPE=C tr -cd 'a-f0-9' | head -c 32
why do not use unix mktemp command:
$ TMPFILE=`mktemp tmp.XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX` && echo $TMPFILE
tmp.MnxEsPDsNUjrzDIiPhnWZKmlAXAO8983
One command, no pipe, no loop:
hexdump -n 16 -v -e '/1 "%02X"' -e '/16 "\n"' /dev/urandom
If you don't need the newline, for example when you're using it in a variable:
hexdump -n 16 -v -e '/1 "%02X"' /dev/urandom
Using "16" generates 32 hex digits.
uuidgen generates exactly this, except you have to remove hyphens. So I found this to be the most elegant (at least to me) way of achieving this. It should work on linux and OS X out of the box.
uuidgen | tr -d '-'
As you probably noticed from each of the answers, you generally have to "resort to a program".
However, without using any external executables, in Bash and ksh:
string=''; for i in {0..31}; do string+=$(printf "%x" $(($RANDOM%16)) ); done; echo $string
in zsh:
string=''; for i in {0..31}; do string+=$(printf "%x" $(($RANDOM%16)) ); dummy=$RANDOM; done; echo $string
Change the lower case x in the format string to an upper case X to make the alphabetic hex characters upper case.
Here's another way to do it in Bash but without an explicit loop:
printf -v string '%X' $(printf '%.2s ' $((RANDOM%16))' '{00..31})
In the following, "first" and "second" printf refers to the order in which they're executed rather than the order in which they appear in the line.
This technique uses brace expansion to produce a list of 32 random numbers mod 16 each followed by a space and one of the numbers in the range in braces followed by another space (e.g. 11 00). For each element of that list, the first printf strips off all but the first two characters using its format string (%.2) leaving either single digits followed by a space each or two digits. The space in the format string ensures that there is then at least one space between each output number.
The command substitution containing the first printf is not quoted so that word splitting is performed and each number goes to the second printf as a separate argument. There, the numbers are converted to hex by the %X format string and they are appended to each other without spaces (since there aren't any in the format string) and the result is stored in the variable named string.
When printf receives more arguments than its format string accounts for, the format is applied to each argument in turn until they are all consumed. If there are fewer arguments, the unmatched format string (portion) is ignored, but that doesn't apply in this case.
I tested it in Bash 3.2, 4.4 and 5.0-alpha. But it doesn't work in zsh (5.2) or ksh (93u+) because RANDOM only gets evaluated once in the brace expansion in those shells.
Note that because of using the mod operator on a value that ranges from 0 to 32767 the distribution of digits using the snippets could be skewed (not to mention the fact that the numbers are pseudo random in the first place). However, since we're using mod 16 and 32768 is divisible by 16, that won't be a problem here.
In any case, the correct way to do this is using mktemp as in Oleg Razgulyaev's answer.
Tested in zsh, should work with any BASH compatible shell!
#!/bin/zsh
SUM=`md5sum <<EOF
$RANDOM
EOF`
FN=`echo $SUM | awk '// { print $1 }'`
echo "Your new filename: $FN"
Example:
$ zsh ranhash.sh
Your new filename: 2485938240bf200c26bb356bbbb0fa32
$ zsh ranhash.sh
Your new filename: ad25cb21bea35eba879bf3fc12581cc9
Yet another way[tm].
R=$(echo $RANDOM $RANDOM $RANDOM $RANDOM $RANDOM | md5 | cut -c -8)
FILENAME="abcdef-$R"
This answer is very similar to fmarks, so I cannot really take credit for it, but I found the cat and tr command combinations quite slow, and I found this version quite a bit faster. You need hexdump.
hexdump -e '/1 "%02x"' -n32 < /dev/urandom
Another thing you can add is running the date command as follows:
date +%S%N
Reads nonosecond time and the result adds a lot of randomness.
The first answer is good but why fork cat if not required.
tr -dc 'a-f0-9' < /dev/urandom | head -c32
Grab 16 bytes from /dev/random, convert them to hex, take the first line, remove the address, remove the spaces.
head /dev/random -c16 | od -tx1 -w16 | head -n1 | cut -d' ' -f2- | tr -d ' '
Assuming that "without resorting to a program" means "using only programs that are readily available", of course.
If you have openssl in your system you can use it for generating random hex (also it can be -base64) strings with defined length. I found it pretty simple and usable in cron in one line jobs.
openssl rand -hex 32
8c5a7515837d7f0b19e7e6fa4c448400e70ffec88ecd811a3dce3272947cb452
Hope to add a (maybe) better solution to this topic.
Notice: this only works with bash4 and some implement of mktemp(for example, the GNU one)
Try this
fn=$(mktemp -u -t 'XXXXXX')
echo ${fn/\/tmp\//}
This one is twice as faster as head /dev/urandom | tr -cd 'a-f0-9' | head -c 32, and eight times as faster as cat /dev/urandom | tr -cd 'a-f0-9' | head -c 32.
Benchmark:
With mktemp:
#!/bin/bash
# a.sh
for (( i = 0; i < 1000; i++ ))
do
fn=$(mktemp -u -t 'XXXXXX')
echo ${fn/\/tmp\//} > /dev/null
done
time ./a.sh
./a.sh 0.36s user 1.97s system 99% cpu 2.333 total
And the other:
#!/bin/bash
# b.sh
for (( i = 0; i < 1000; i++ ))
do
cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 32 > /dev/null
done
time ./b.sh
./b.sh 0.52s user 20.61s system 113% cpu 18.653 total
If you are on Linux, then Python will come pre-installed. So you can go for something similar to the below:
python -c "import uuid; print str(uuid.uuid1())"
If you don't like the dashes, then use replace function as shown below
python -c "import uuid; print str(uuid.uuid1()).replace('-','')"
What is the simplest way to remove all the carriage returns \r from a file in Unix?
I'm going to assume you mean carriage returns (CR, "\r", 0x0d) at the ends of lines rather than just blindly within a file (you may have them in the middle of strings for all I know). Using this test file with a CR at the end of the first line only:
$ cat infile
hello
goodbye
$ cat infile | od -c
0000000 h e l l o \r \n g o o d b y e \n
0000017
dos2unix is the way to go if it's installed on your system:
$ cat infile | dos2unix -U | od -c
0000000 h e l l o \n g o o d b y e \n
0000016
If for some reason dos2unix is not available to you, then sed will do it:
$ cat infile | sed 's/\r$//' | od -c
0000000 h e l l o \n g o o d b y e \n
0000016
If for some reason sed is not available to you, then ed will do it, in a complicated way:
$ echo ',s/\r\n/\n/
> w !cat
> Q' | ed infile 2>/dev/null | od -c
0000000 h e l l o \n g o o d b y e \n
0000016
If you don't have any of those tools installed on your box, you've got bigger problems than trying to convert files :-)
tr -d '\r' < infile > outfile
See tr(1)
The simplest way on Linux is, in my humble opinion,
sed -i.bak 's/\r$//g' <filename>
-i will edit the file in place, while the .bak will create a backup of the original file by making a copy of your file and adding the extension .bak at the end. (You can specify what ever you want after the -i, or specify only -i to not create a backup.)
The strong quotes around the substitution operator 's/\r//' are essential. Without them the shell will interpret \r as an escape+r and reduce it to a plain r, and remove all lower case r. That's why the answer given above in 2009 by Rob doesn't work.
And adding the /g modifier ensures that even multiple \r will be removed, and not only the first one.
Old School:
tr -d '\r' < filewithcarriagereturns > filewithoutcarriagereturns
There's a utility called dos2unix that exists on many systems, and can be easily installed on most.
sed -i s/\r// <filename> or somesuch; see man sed or the wealth of information available on the web regarding use of sed.
One thing to point out is the precise meaning of "carriage return" in the above; if you truly mean the single control character "carriage return", then the pattern above is correct. If you meant, more generally, CRLF (carriage return and a line feed, which is how line feeds are implemented under Windows), then you probably want to replace \r\n instead. Bare line feeds (newline) in Linux/Unix are \n.
If you are a Vi user, you may open the file and remove the carriage return with:
:%s/\r//g
or with
:1,$ s/^M//
Note that you should type ^M by pressing ctrl-v and then ctrl-m.
Someone else recommend dos2unix and I strongly recommend it as well. I'm just providing more details.
If installed, jump to the next step. If not already installed, I would recommend installing it via yum like:
yum install dos2unix
Then you can use it like:
dos2unix fileIWantToRemoveWindowsReturnsFrom.txt
Once more a solution... Because there's always one more:
perl -i -pe 's/\r//' filename
It's nice because it's in place and works in every flavor of unix/linux I've worked with.
Removing \r on any UNIX® system:
Most existing solutions in this question are GNU-specific, and wouldn't work on OS X or BSD; the solutions below should work on many more UNIX systems, and in any shell, from tcsh to sh, yet still work even on GNU/Linux, too.
Tested on OS X, OpenBSD and NetBSD in tcsh, and on Debian GNU/Linux in bash.
With sed:
In tcsh on an OS X, the following sed snippet could be used together with printf, as neither sed nor echo handle \r in the special way like the GNU does:
sed `printf 's/\r$//g'` input > output
With tr:
Another option is tr:
tr -d '\r' < input > output
Difference between sed and tr:
It would appear that tr preserves a lack of a trailing newline from the input file, whereas sed on OS X and NetBSD (but not on OpenBSD or GNU/Linux) inserts a trailing newline at the very end of the file even if the input is missing any trailing \r or \n at the very end of the file.
Testing:
Here's some sample testing that could be used to ensure this works on your system, using printf and hexdump -C; alternatively, od -c could also be used if your system is missing hexdump:
% printf 'a\r\nb\r\nc' | hexdump -C
00000000 61 0d 0a 62 0d 0a 63 |a..b..c|
00000007
% printf 'a\r\nb\r\nc' | ( sed `printf 's/\r$//g'` /dev/stdin > /dev/stdout ) | hexdump -C
00000000 61 0a 62 0a 63 0a |a.b.c.|
00000006
% printf 'a\r\nb\r\nc' | ( tr -d '\r' < /dev/stdin > /dev/stdout ) | hexdump -C
00000000 61 0a 62 0a 63 |a.b.c|
00000005
%
If you're using an OS (like OS X) that doesn't have the dos2unix command but does have a Python interpreter (version 2.5+), this command is equivalent to the dos2unix command:
python -c "import sys; import fileinput; sys.stdout.writelines(line.replace('\r', '\n') for line in fileinput.input(mode='rU'))"
This handles both named files on the command line as well as pipes and redirects, just like dos2unix. If you add this line to your ~/.bashrc file (or equivalent profile file for other shells):
alias dos2unix="python -c \"import sys; import fileinput; sys.stdout.writelines(line.replace('\r', '\n') for line in fileinput.input(mode='rU'))\""
... the next time you log in (or run source ~/.bashrc in the current session) you will be able to use the dos2unix name on the command line in the same manner as in the other examples.
you can simply do this :
$ echo $(cat input) > output
Here is the thing,
%0d is the carriage return character. To make it compatabile with Unix. We need to use the below command.
dos2unix fileName.extension fileName.extension
try this to convert dos file into unix file:
fromdos file
For UNIX... I've noticed dos2unix removed Unicode headers form my UTF-8 file. Under git bash (Windows), the following script seems to work nicely. It uses sed. Note it only removes carriage-returns at the ends of lines, and preserves Unicode headers.
#!/bin/bash
inOutFile="$1"
backupFile="${inOutFile}~"
mv --verbose "$inOutFile" "$backupFile"
sed -e 's/\015$//g' <"$backupFile" >"$inOutFile"
If you are running an X environment and have a proper editor (visual studio code), then I would follow the reccomendation:
Visual Studio Code: How to show line endings
Just go to the bottom right corner of your screen, visual studio code will show you both the file encoding and the end of line convention followed by the file, an just with a simple click you can switch that around.
Just use visual code as your replacement for notepad++ on a linux environment and you are set to go.
Using sed
sed $'s/\r//' infile > outfile
Using sed on Git Bash for Windows
sed '' infile > outfile
The first version uses ANSI-C quoting and may require escaping \ if the command runs from a script. The second version exploits the fact that sed reads the input file line by line by removing \r and \n characters. When writing lines to the output file, however, it only appends a \n character. A more general and cross-platform solution can be devised by simply modifying IFS
IFS=$'\r\n' # or IFS+=$'\r' if the lines do not contain whitespace
printf "%s\n" $(cat infile) > outfile
IFS=$' \t\n' # not necessary if IFS+=$'\r' is used
Warning: This solution performs filename expansion (*, ?, [...] and more if extglob is set). Use it only if you are sure that the file does not contain special characters or you want the expansion.
Warning: None of the solutions can handle \ in the input file.
cat input.csv | sed 's/\r/\n/g' > output.csv
worked for me
I've used python for it, here my code;
end1='/home/.../file1.txt'
end2='/home/.../file2.txt'
with open(end1, "rb") as inf:
with open(end2, "w") as fixed:
for line in inf:
line = line.replace("\n", "")
line = line.replace("\r", "")
fixed.write(line)
Though it's a older post, recently I came across with same problem. As I had all the files to rename inside /tmp/blah_dir/ as each file in this directory had "/r" trailing character ( showing "?" at end of file), so doing it script way was only I could think of.
I wanted to save final file with same name (without trailing any character).
With sed, problem was the output filename which I was needed to mention something else ( which I didn't want).
I tried other options as suggested here (not considered dos2unix because of some limitations) but didn't work.
I tried with "awk" finally which worked where I used "\r" as delimiter and taken the first part:
trick is:
echo ${filename}|awk -F"\r" '{print $1}'
Below script snippet I used ( where I had all file had "\r" as trailing character at path /tmp/blah_dir/) to fix my issue:
cd /tmp/blah_dir/
for i in `ls`
do
mv $i $(echo $i | awk -F"\r" '{print $1}')
done
Note: This example is not very exact though close to what I worked (Mentioning here just to give the better idea about what I did)
I made this shell-script to remove the \r character. It works in solaris and red-hat:
#!/bin/ksh
LOCALPATH=/Any_PATH
for File in `ls ${LOCALPATH}`
do
ARCACT=${LOCALPATH}/${File}
od -bc ${ARCACT}|sed -n 'p;n'|sed 's/015/012/g'|awk '{$1=""; print $0}'|sed 's/ /\\/g'|awk '{printf $0;}'>${ARCACT}.TMP
printf "`cat ${ARCACT}.TMP`"|sed '/^$/d'>${ARCACT}
rm ${ARCACT}.TMP
done
exit 0