Ubuntu – How to change extension of multiple files recursively from the command line

bashbatch-renamecommand linerename

I have many files with .abc extension and want to change them to .edefg
How to do this from command line ?

I have a root folder with many sub-folders, so the solution should work recursively.

Best Answer

A portable way (which will work on any POSIX compliant system):

find /the/path -depth -name "*.abc" -exec sh -c 'mv "$1" "${1%.abc}.edefg"' _ {} \;

In bash4, you can use globstar to get recursive globs (**):

shopt -s globstar
for file in /the/path/**/*.abc; do
  mv "$file" "${file%.abc}.edefg"
done

The (perl) rename command in Ubuntu can rename files using perl regular expression syntax, which you can combine with globstar or find:

# Using globstar
shopt -s globstar
files=(/the/path/**/*.abc)  

# Best to process the files in chunks to avoid exceeding the maximum argument 
# length. 100 at a time is probably good enough. 
# See http://mywiki.wooledge.org/BashFAQ/095
for ((i = 0; i < ${#files[@]}; i += 100)); do
  rename 's/\.abc$/.edefg/' "${files[@]:i:100}"
done

# Using find:
find /the/path -depth -name "*.abc" -exec rename 's/\.abc$/.edefg/' {} +

Also see http://mywiki.wooledge.org/BashFAQ/030

Related Solutions

Ubuntu – Delete all files except specified files/folders using command line

You can use GLOBIGNORE to set the names that will be ignored while globbing and then use * to match all other files/directories:

GLOBIGNORE='a:b:x'; rm -r *

Example:

$ tree 
.
├── a
│   ├── 1
│   ├── 2
│   └── 3
├── b
│   ├── 1
│   ├── 2
│   └── 3
├── c
│   ├── 1
│   ├── 2
│   └── 3
├── x
├── y
└── z

/NASA$ GLOBIGNORE='a:b:x'

/NASA$ rm -r *

/NASA$ tree 
.
├── a
│   ├── 1
│   ├── 2
│   └── 3
├── b
│   ├── 1
│   ├── 2
│   └── 3
└── x

Alternately, you can use find, from the NASA directory:

find . -maxdepth 1 ! -name '.' ! -regex '.*/\(a\|b\|x\)$' -exec rm -r {} +

Example:

/NASA$ tree 
.
├── a
│   ├── 1
│   ├── 2
│   └── 3
├── b
│   ├── 1
│   ├── 2
│   └── 3
├── c
│   ├── 1
│   ├── 2
│   └── 3
├── x
├── y
└── z


/NASA$ find . -maxdepth 1 ! -name '.' ! -regex '.*/\(a\|b\|x\)$' -exec rm -r {} +


/NASA$ tree 
.
├── a
│   ├── 1
│   ├── 2
│   └── 3
├── b
│   ├── 1
│   ├── 2
│   └── 3
└── x

Ubuntu – Print sub-folder name and content of result.txt to .csv

I think find is the right choice:

find */ -name "result.txt" -exec bash -c 'printf "%s,%s\n" "${0%%/*}" "$(cat $0)"' {} \;

Example run

$ echo r1 >a/b/result.txt
$ echo r2 >c/result.txt
$ tree
.
├── a
│   └── b
│       └── result.txt
└── c
    └── result.txt
$ find */ -name "result.txt" -exec bash -c 'printf "%s,%s\n" "${0%%/*}" "$(cat $0)"' {} \;
a,r1
c,r2

Explanations

This find command searches every file in or under the current directory of the name result.txt and executes the printf command in a bash subshell. The printf command prints the subdir's name, a comma and the file content followed by a \newline. If you want to write this output to a file, just append e.g. >final.csv to the command.

Even simpler

is the -printf approach suggested by steeldriver:

$ find */ -name 'result.txt' -printf '%H,' -exec cat {} \;
a/,r1
c/,r2

This prints an additional slash in the first column which you can easily remove by piping the output through e.g. sed 's|/,|,|'.

Merging multiline `result.txt` content into one cell

To replace newline characters with e.g. spaces just replace cat with sed ":a;N;\$!ba;s/\n/ /g" in one of the above commands, e.g.

$ find */ -name "result.txt" -exec bash -c 'printf "%s,%s\n" "${0%%/*}" "$(sed ":a;N;\$!ba;s/\n/ /g" $0)"' {} \;
a,r1 r1
c,r2

If you want some other string as the delimiter replace the / / part with /your_delimiter/, but keep the slashes.