Difference between revisions of "Shell"

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m (→‎^ To Research: add note about Zephyr header file zephyr/include/zephyr/toolchain/xcc_missing_defs.h.)
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Shell Scripting
 
Shell Scripting
  
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== [[#top|^]] OVERVIEW ==
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This local page for Bash shell scripts and notes on shell scripting.
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== [[#top|^]] Bash Built-in Variables ==
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Some links to useful articles discussing `bash` built-in variables:
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*  https://avpres.net/Bash/builtin_shell_variables
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*  https://www.gnu.org/software/bash/manual/html_node/Bash-Variables.html
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Bash's built-in variables with short names, as listed in Kernigan and Ritchie's "Unix Programming" book and at the first linked article above:
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<pre>
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$0
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    The first element passed to the shell is the command name.
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$n
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    The nth argument passed on the command line. If n ≥ 10, then the syntax must be ${n}.
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$*
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    All the arguments on the command line. The values are separated by the first character in the shell variable IFS: (${1} … ${n}). See also: the IFS entry in Other Shell Variables.
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$@
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    All the arguments on the command line. The values are individually quoted: ("${1}" … "${n}").
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$#
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    The number of command-line arguments.
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$?
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    The exit value of the last executed command.
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$_
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    The last argument of the previous command.
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$!
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    The process ID of the most recent background process.
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</pre>
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<!-- odne komentar -->
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== [[#top|^]] Rename Badly Named Files ==
  
 
How to produce a usable filename which contains <ESC> characters, and to rename that badly named file:
 
How to produce a usable filename which contains <ESC> characters, and to rename that badly named file:
  
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  $ ls -i
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  9704871 ''$'\033\033'  9703029  CMakeLists.txt  10899590  dts          9708845  samples
 
   $ ls -q `find . -inum 9704871`
 
   $ ls -q `find . -inum 9704871`
 
   './'$'\033\033'
 
   './'$'\033\033'
 
   $ mv './'$'\033\033' betterfilename
 
   $ mv './'$'\033\033' betterfilename
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<!-- odne komentar -->
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<span id="nn_anchor__shell__helper_script_git_diff-tree"></span>
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== [[#top|^]] Git Diff-tree Helper Script ==
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A helper script for calling `git diff-tree`, which can be used to determine at which project commit one or more files have changed:
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<pre>
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#!/bin/bash
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CMD_GIT=/usr/bin/git
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$CMD_GIT log --oneline | head | cut -d " " -f 1
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echo "2024-01-31 git diff-tree helper script in progress . . ."
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echo "got $# arguments, arg one single quoted is '$1'"
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hashes=`$CMD_GIT log --oneline | head -n ${1} | cut -d " " -f 1`
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echo "In $PWD found git commit hashes:"
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echo " " $hashes
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#i=1
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#for hash in $hashes; do echo "("$i")" $hash; (( i++ )); done
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#echo "Files changed between commit pairs youngest pairings to oldest:
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#for hash in $hashes; do echo "Files changed in git commit:"; git diff-tree -r $hash; echo; done
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for hash in $hashes
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    do echo "Files changed in git commit:"
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    git log -1 --oneline $hash
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    git diff-tree -r $hash
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    echo
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done
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echo "done"
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exit 0
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</pre>
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<!-- odne komentar -->
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== [[#top|^]] To Research ==
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[ ] Look up `git ls-files` and its options.
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[ ] Review `xargs` called with the dash zero option.
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Interesting header file from Zephyr RTOS 3.4.0:
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`zephyr/include/zephyr/toolchain/xcc_missing_defs.h`
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 +
<!-- odne komentar -->

Revision as of 22:45, 7 June 2024

Shell Scripting

^ OVERVIEW

This local page for Bash shell scripts and notes on shell scripting.

^ Bash Built-in Variables

Some links to useful articles discussing `bash` built-in variables:

Bash's built-in variables with short names, as listed in Kernigan and Ritchie's "Unix Programming" book and at the first linked article above: 

$0
    The first element passed to the shell is the command name.
$n
    The nth argument passed on the command line. If n ≥ 10, then the syntax must be ${n}.
$*
    All the arguments on the command line. The values are separated by the first character in the shell variable IFS: (${1} … ${n}). See also: the IFS entry in Other Shell Variables.
$@
    All the arguments on the command line. The values are individually quoted: ("${1}" … "${n}").
$#
    The number of command-line arguments.
$?
    The exit value of the last executed command.
$_
    The last argument of the previous command.
$!
    The process ID of the most recent background process.

^ Rename Badly Named Files

How to produce a usable filename which contains <ESC> characters, and to rename that badly named file: 

 $ ls -i
 9704871 $'\033\033'   9703029  CMakeLists.txt  10899590  dts          9708845  samples
 $ ls -q `find . -inum 9704871`
 './'$'\033\033'
 $ mv './'$'\033\033' betterfilename

^ Git Diff-tree Helper Script

A helper script for calling `git diff-tree`, which can be used to determine at which project commit one or more files have changed: 

#!/bin/bash

CMD_GIT=/usr/bin/git

$CMD_GIT log --oneline | head | cut -d " " -f 1

echo "2024-01-31 git diff-tree helper script in progress . . ."
echo "got $# arguments, arg one single quoted is '$1'"

hashes=`$CMD_GIT log --oneline | head -n ${1} | cut -d " " -f 1`
echo "In $PWD found git commit hashes:"
echo " " $hashes

#i=1
#for hash in $hashes; do echo "("$i")" $hash; (( i++ )); done

#echo "Files changed between commit pairs youngest pairings to oldest:
#for hash in $hashes; do echo "Files changed in git commit:"; git diff-tree -r $hash; echo; done
for hash in $hashes
    do echo "Files changed in git commit:"
    git log -1 --oneline $hash
    git diff-tree -r $hash
    echo
done

echo "done"

exit 0


^ To Research

[ ] Look up `git ls-files` and its options.

[ ] Review `xargs` called with the dash zero option.

Interesting header file from Zephyr RTOS 3.4.0:

`zephyr/include/zephyr/toolchain/xcc_missing_defs.h`


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