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I have some filename in a .txt file and some other filename in another .txt file. I want to rename files stored in that folder from filename in the text file line by line.
FROM :
$cat oldname.txt
file1.mp4
file2.mp4
TO :
$cat newname.txt
video1.mp4
video2.mp4
I want some bash script that can execute mv command line by line for each file.
Like
$mv file1.mp4 video1.mp4
Use a proper loop over the file to rename with bash . Open the files separately in different file-descriptors.
#!/bin/bash
while read oldname <&3 && read newname <&4
do
mv "$oldname" "$newname"
done 3<oldname.txt 4<newname.txt
Try:
while read oldname; do
read -u 3 newname
echo mv $oldname $newname
done < oldname.txt 3< newname.txt
This will merely echo the commands. If you like the result, omit the echo.
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I am trying to copy specific words from a text file in a directory to another using grep. I have the retrieval of the words I want from the text file, now I just am wondering how I would go about moving it another text file, say in my home directory.
Here is the grep command.
grep -E '^.[*ing]{5}$' words
and here is what I have tried
grep -E '^.[*ing]{5}$' words > words.txt $home
grep -E '^.[*ing]{5}$' words > words.txt /home/
Any help is appreciated!
grep -E '^.[*ing]{5}$' words > /home/words.txt
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Closed 6 years ago.
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I have a couple of files that needs to be renamed by using a linux shell script. I need to insert the text "ID" next to the second character of the filenames:
HP0001.txt
HP0002.txt
HP0003.txt
the script should be able to rename it to
HPID0001.txt
HPID0002.txt
HPID0003.txt
If it's just a "couple of files", it's probably easiest to just rename them manually.
Otherwise, here's a trivial script you can adapt:
for f in HP*.txt; do
f2=`echo $f|sed -e 's/HP/HPID/'`
echo mv $f $f2
done
SAMPLE OUTPUT:
ls HP*
HP001.txt HP002.txt HP003.txt
bash ./tmp.sh
mv HP001.txt HPID001.txt
mv HP002.txt HPID002.txt
mv HP003.txt HPID003.txt
Files in directory before script execution :
HP0001.txt
HP0002.txt
HP0003.txt
main
main script content
cat main.sh
for file in *
do
new_name=$(echo $file|sed 's/HP/&ID/')
mv $file $new_name 2>/dev/null
done
Directory contents after script execution:
ls -1
HPID0001.txt
HPID0002.txt
HPID0003.txt
main
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Closed 8 years ago.
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Just curious, this is normal-expected behavior of ls:
user#host:~$ ls
Codes Documents Music Pictures Templates
Desktop Downloads Papers Public Videos
But when I use ls with pipe/redirection, it behave like ls -1:
user#host:~$ ls | cat
Codes
Desktop
Documents
Downloads
Music
Papers
Pictures
Public
Templates
Videos
Why? (and how to write such program that gives difference output between stdout and pipe like this?)
P.S. I also set alias l='ls -F', and this time pipe/redirection is no longer ls -1 style:
user#host:~$ l | cat
Codes/ Documents/ Music/ Pictures/ Templates/
Desktop/ Downloads/ Papers/ Public/ Videos/
Without using the alias, it does the command in ls -1 style, however:
$ ls -F | cat
Codes/
Desktop/
Documents/
Downloads/
Music/
Papers/
Pictures/
Public/
Templates/
Videos/
You can check this line from the source:
if (format == long_format)
format = (isatty (STDOUT_FILENO) ? many_per_line : one_per_line);
It uses the isatty function to check if stdout points to a tty, and to print many_per_line if it does or one_per_line if it does not.
Here is how GNU ls does it (ls.c):
if (isatty (STDOUT_FILENO))
{
format = many_per_line;
}
else
{
format = one_per_line;
}
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Closed 9 years ago.
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It seems like a trivial issue, but I did not find a solution.
I have a number of log files in a php installation on Debian/Linux that tend to grow quite a bit and I would like to trim nightly to the last 500 lines or so.
How do I do it, possibly in shell and applying a command to *log?
For this, I would suggest to use logrotate with a configuration to your liking instead of programming your own script.
There might be a more elegant way to do this programmatically, but it is possible to use tail and a for-loop for this:
for file in *.log; do
tail -500 "$file" > "$file.tmp"
mv -- "$file.tmp" "$file"
done
If you want to save history of older files, you should check out logrotate.
Otherwise, this can be done trivially with the command line:
LOGS="/var/log"
MAX_LINES=500
find "$LOGS" -type f -name '*.log' -print0 | while read -d '' file; do
tmp=$(mktemp)
tail -n $MAX_LINES $file > $tmp
mv $tmp $file
done
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I know that
cat file1 >> file2
would append the contents of file1 at the end of file2. On the other hand, how can I append the contents of file1 at the beginning of file 2, and not at its end?
Actually, i have a single master file M, and several other files in a directory D. I want to append the contents of file M at the beginning of all the files in the directory D.
Just do:
cat file1 file2 > tmp && mv tmp file2
For each file you could do:
cat MASTER file >> file.tmp
And then move file.tmp over file.
You will have to use a temporary file and rename it after merge.
Example:
echo -e "a\nb\nc" > LETTERS
echo -e "1\n2\n3" > NUMBERS
cat NUMBERS LETTERS > TMP
mv TMP LETTERS
cat LETTERS
Your command might look something like:
for file in $( find -name "*.java" ); do cat PREPEND ${file} > ${file}.tmp; mv ${file}.tmp ${file}; done