UNIX for Beginners Questions & Answers

set -vx

for i in ~/Shell_Practice/rename/*.txt 
do  
    t=`(echo $i | awk gsub("file","newfile"))`
    mv $i $t
 done

atomic@atomic-VirtualBox:~/Shell_Practice/rename$ ./rename.sh

for i in ~/Shell_Practice/rename/*.txt 
do  
    t=`(echo $i | awk gsub("file","newfile"))`
    mv $i $t
 done
++ for i in ~/Shell_Practice/rename/*.txt
./rename.sh: command substitution: line 5: syntax error near unexpected token `('
./rename.sh: command substitution: line 5: `(echo $i | awk gsub("file","newfile"))'
++ t=
++ mv /home/atomic/Shell_Practice/rename/file10.txt
mv: missing destination file operand after '/home/atomic/Shell_Practice/rename/file10.txt'
Try 'mv --help' for more information.
++ for i in ~/Shell_Practice/rename/*.txt
./rename.sh: command substitution: line 5: syntax error near unexpected token `('
./rename.sh: command substitution: line 5: `(echo $i | awk gsub("file","newfile"))'
++ t=
++ mv /home/atomic/Shell_Practice/rename/file1.txt
mv: missing destination file operand after '/home/atomic/Shell_Practice/rename/file1.txt'
 Try 'mv --help' for more information.

atomic@atomic-VirtualBox:~/Shell_Practice/rename$ ls
file10.txt  file2.txt  file4.txt  file6.txt  file8.txt  rename.sh
file1.txt   file3.txt  file5.txt  file7.txt  file9.txt

mv a.txt a.txt

prename 's/file/newfile/' ~/Shell_Practice/rename/*.txt

prename -vn 's/file/newfile/' ~/Shell_Practice/rename/*.txt

atomic@atomic-VirtualBox:~$ uname -a
Linux atomic-VirtualBox 4.15.0-42-generic #45-Ubuntu SMP Thu Nov 15 19:32:57 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
atomic@atomic-VirtualBox:~$ echo $SHELL
/bin/bash

for i in ~/Shell_Practice/rename/*.txt
  do    t=${i/"file"/"newfile"}
        [ ! "$i" = "$t" ] && echo mv "$i" "$t"
  done

for i in ~/Shell_Practice/rename/*.txt 
do  
  if [ -e "$i" ]; then
    mv -- "$i" "${i/file/newfile}"
  fi
done

shopt -s nullglob
for i in ~/Shell_Practice/rename/*.txt 
do  
  mv -- "$i" "${i/file/newfile}"
done

mv file1 file2

awk

sed

#!/bin/bash
set -vx

for path in ~/Shell_Practice/rename/*file*.txt 
do	[ -e "$path" ] && printf '%s\n' "$path"
done | awk '
{	old = $0
	gsub(/file/, "newfile")
	print "echo mv --", "\""old"\"", "\""$0"\""
}' | bash -xv

#!/bin/bash
set -vx

for path in ~/Shell_Practice/rename/*file*.txt 
do	[ -e "$path" ] && printf '%s\n' "$path"
done | sed 'p; s/file/newfile/g' | while read -r oldpath && read -r newpath
do	echo mv -- "$oldpath" "$newpath"
done