Linux - File

> Procedural Languages > Bash Shell and (Unix|Linux) Utilities (XCU) > Bash - File System

1 - About

Linux file management

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3 - Basic

4 - Type

4.1 - hidden

A full stop '.' before the name of the file makes it a hidden file. Example '.bash'

Sh - Hidden files

4.2 - Metadata

5 - Management

5.1 - Get

5.1.1 - Filename and extension

Using Parameters Expansion Removal

fileFullName=$(basename "$filePath")
# or
fileFullName="${filePath##*/}"
extension="${fileFullName##*.}"
filename="${fileFullName%.*}"
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5.1.2 - parent directory

  • From a path string where the file does not exist
VAR=/filedoesnt/exist
echo ${VAR%/*}
/filedoesnt
  • dirname returns the first parent of an existing path file.
dirname "dir/file"
dir

5.1.3 - File Permission

5.1.4 - File exist

if [ ! -f $PATH ]; then
    echo "File $PATH not found!"
fi

5.2 - Comparison

cmp --silent $old $new || echo "files are different"
cmp -b $old $new 

See also : diff

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5.3 - Diff

diff file1 file2 | cat -t

where:

  • ^M for CR,
  • ^I for tab

See also: comparison

5.4 - Filter a list of files ?

This command below gives you all files in the current directory which begin by elfutils

dir | grep -i elfutils
elfutils-0.137-3.el5.i386.rpm
elfutils-devel-0.137-3.el5.i386.rpm
elfutils-devel-static-0.137-3.el5.i386.rpm
elfutils-libelf-0.137-3.el5.i386.rpm
elfutils-libelf-devel-0.137-3.el5.i386.rpm
elfutils-libelf-devel-static-0.137-3.el5.i386.rpm
elfutils-libs-0.137-3.el5.i386.rpm
  • find can do it recursviely

5.5 - Remove a file?

Permission: In UNIX and Linux, the ability to remove a file is determined by the access bits of parent directory

chmod 777 .
chown hi-adm:hi-adm .

With the command rm

Example:

  • Basic
rm filename.extension
  • Prompts for confirmation before removing a file
rm -i filename.extension
  • Force removal of the file regardless of it bieng write-protected or open
rm -f filename.extension
  • Remove files recursively in 'directory'
rm -r directory

More … perform the man commando

man rm

5.6 - Copy 1 or multiple file

cp - Copy one or more files to another location.

Example::

  • Copy of a directory with resistivity:
cp -r dirtocopy newdir
  • Copy two files
cp myFile1.txt myFile2.txt myDirDestination
  • Copy all files of directory
cp * myDirDestination
# or
cp /myDirSource/* /myDirDestination
  • Copy all txt files (with a pattern)
cp *.txt myDirDestination

5.7 - Move / Rename

  • mv - Moves or renames file

5.8 - Transfer

5.9 - See the content

  • cat,
  • head (Displays first 10 lines of file),
  • tail - Displays last 10 lines of file,
  • tac (for reverse output)
  • less and more let you scroll the text files

5.10 - Search a file by name

  • locate - List files that match a pattern.

Locate all file with a regular expression. In this example all file which begin with sp and end up with the extension msb.

locate -r "sp.*\.msb"
  • find - search for files in a directory hierarchy.
find /my/directory -name myFile.extension

5.11 - Search files based on date

touch -d '2011-12-31 10:22' foo
find . -newer foo

5.12 - Search the content of files

5.13 - File Architecture (32 or 64 bit)

File Architecture

file fileName

Example:

file java
/bin/java: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped

5.14 - Iterate

OLDIFS=$IFS; IFS=$'\n'; 
filelines=`cat $filename`
for line in $filelines ; do
    echo $line
done
IFS=$OLDIFS

6 - List of command

  • ls - List contents of a directory
  • which - Displays path to command
  • whereis - locate the binary, source, and manual page files for a command

7 - Content

lang/bash/fs/file.txt · Last modified: 2019/06/12 10:58 by gerardnico