linux:start

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linux:start [2026/04/26 22:15] – mhlinux:start [2026/07/02 21:26] (current) – [File operations] mh
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 === Mass renaming === === Mass renaming ===
  
-Uppercase .JPG to lowercase .jpg+__**Changing an extension:**__
  
 <code bash> <code bash>
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 </code> </code>
  
-Alternative (rename tool):+__**Changing a prefix:**__ 
 + 
 +<code bash> 
 +for i in "prefix"*.png; do 
 +  mv -n -- "$i" "${i/#prefix/another prefix}" 
 +done 
 +</code> 
 + 
 +  * ''"prefix"*.png'' targets only files beginning with the selected prefix, so unrelated files in the folder are ignored. 
 +  * ''${i/#prefix/another prefix}'' replaces only the prefix at the beginning of the filename. If the same text appears later in the filename, it is left untouched. 
 +  * In Bash parameter expansion, the ''#'' before ''prefix'' means “match only at the start of the variable value”. Without ''#'', Bash would replace the first matching occurrence anywhere in the filename. 
 +  * ''mv -n'' prevents overwriting an existing file if the renamed target already exists. 
 +  * ''--'' tells ''mv'' that everything after it is a filename, not an option. This protects against unusual filenames starting with ''-''. 
 +  * ''"$i"'' keeps the original filename safely quoted, so spaces and special characters in filenames are preserved. 
 + 
 +__**Alternative (rename tool):**__
  
 <code bash> <code bash>
 rename 's/\.JPG$/.jpg/' *.JPG rename 's/\.JPG$/.jpg/' *.JPG
 </code> </code>
 +
 +  * Use the ''for ... done'' + ''mv -n --'' loop for safe, explicit prefix renaming.
 +  * Use ''rename'' for concise regex-based changes, especially extension changes such as ''.JPG'' to ''.jpg''.
 +  * On Linux Mint / Ubuntu, ''rename 's/\.JPG$/.jpg/' *.JPG'' usually works because the available ''rename'' is the Perl-style tool.
 +  * The ''rename'' command is not fully portable across all Linux distributions, because different systems may ship different versions with different syntax.
 +  * For safety, preview first with ''rename -n 's/\.JPG$/.jpg/' *.JPG''.
  
 ---- ----
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 ---- ----
 +
 +====== User Environment ======
  
 ===== PATH ===== ===== PATH =====
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 It often reduces file size, especially with image-heavy PDFs, but this is not guaranteed. It often reduces file size, especially with image-heavy PDFs, but this is not guaranteed.
 </WRAP> </WRAP>
- 
- 
- 
- 
-===== Data recovery ===== 
- 
-Use **TestDisk** / **PhotoRec** as a first recovery tool. 
- 
-  * **TestDisk** attempts partition repair and file undelete when filesystem metadata is still usable. 
-  * **PhotoRec** performs file carving by signature. It can recover files from damaged filesystems, but filenames and folder structure are usually lost. 
- 
-Do not write recovered files to the source disk. 
- 
-==== PhotoRec: recovered MOV files ==== 
- 
-For some recovered ''.mov'' files, PhotoRec may split the video into separate ''ftyp'' and ''mdat'' parts. 
- 
-In PhotoRec ''FileOpts'', enable: 
- 
-<code> 
-[X] mov/mdat Recover mdat atom as a separate file 
-</code> 
- 
-Sort recovered files by name, then try concatenating matching parts: 
- 
-<code bash> 
-cat f123_ftyp.mov f456_mdat.mov > recovered_1.mov 
-cat f456_mdat.mov f123_ftyp.mov > recovered_2.mov 
-</code> 
- 
-One order may produce a usable file. 
- 
-Sometimes the header/container part may be ''.mp4'' while the media data part is ''.mov'': 
- 
-<code bash> 
-cat f54114560.mp4 f51781632_mdat.mov > recovered.mov 
-</code> 
- 
-Note: This is a recovery attempt, not a guaranteed repair method. For valuable data, stop using the disk immediately and clone/image it before experimenting. 
- 
  
 ===== Video playback (minimal UI) ===== ===== Video playback (minimal UI) =====
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 osdlevel=0 osdlevel=0
 </code> </code>
 +
 +
 +
 +====== Specialized & Recovery ======
 +
 +===== Data recovery =====
 +
 +Use **TestDisk** / **PhotoRec** as a first recovery tool.
 +
 +  * **TestDisk** attempts partition repair and file undelete when filesystem metadata is still usable.
 +  * **PhotoRec** performs file carving by signature. It can recover files from damaged filesystems, but filenames and folder structure are usually lost.
 +
 +Do not write recovered files to the source disk.
 +
 +==== PhotoRec: recovered MOV files ====
 +
 +For some recovered ''.mov'' files, PhotoRec may split the video into separate ''ftyp'' and ''mdat'' parts.
 +
 +In PhotoRec ''FileOpts'', enable:
 +
 +<code>
 +[X] mov/mdat Recover mdat atom as a separate file
 +</code>
 +
 +Sort recovered files by name, then try concatenating matching parts:
 +
 +<code bash>
 +cat f123_ftyp.mov f456_mdat.mov > recovered_1.mov
 +cat f456_mdat.mov f123_ftyp.mov > recovered_2.mov
 +</code>
 +
 +One order may produce a usable file.
 +
 +Sometimes the header/container part may be ''.mp4'' while the media data part is ''.mov'':
 +
 +<code bash>
 +cat f54114560.mp4 f51781632_mdat.mov > recovered.mov
 +</code>
 +
 +Note: This is a recovery attempt, not a guaranteed repair method. For valuable data, stop using the disk immediately and clone/image it before experimenting.
 +
 +
  
 ===== Using Apple USB SuperDrive ===== ===== Using Apple USB SuperDrive =====
  • linux/start.1777234554.txt.gz
  • Last modified: 2026/04/26 22:15
  • by mh