Linux shell/Commands - Revision history

Pio2pio: /* Timestamp in the filename */

2023-12-19T15:15:09Z

Timestamp in the filename

@@ Line 305: / Line 305: @@
 ;References:
 *[https://stackoverflow.com/questions/50907211/what-is-a-tai64-time-format What is a TAI64 time format?] Stackoverfolow
 == Timestamp in the filename  ==
 <source lang="bash">

Pio2pio: /* Search and Replace */

2022-07-18T19:15:45Z

Search and Replace

← Older revision		Revision as of 21:15, 18 July 2022
Line 818:		Line 818:

	=== Search and Replace ===		=== Search and Replace ===
			Expansion operators:
			<code>/</code> - substitutes 1st match
			<code>//</code> - substitutes all matches

	<source lang="bash">		<source lang="bash">
	# ~~string we wish to replace~~ '_' with '/' which is common turning a ~~tring~~ into a path		# Example 1. Replace all '_' with '/' which is a common way turning a string into a path
	~~var~~=secret_loc-a_branch1_branch2_key1		STRING=secret_loc-a_branch1_branch2_key1
	echo "path: ${~~var~~//_//}"		echo "path: ${STRING//_//}"
	path: secret/loc-a/branch1/branch2/key1		path: secret/loc-a/branch1/branch2/key1
	# ~~/ :- substitutes~~ 1st match
	# // :- ~~substitutes all matches~~		# Example 2. Replace 1st match '-' with '_'
			STRING=gke-dev
			echo ${STRING/-/_} # -> gke_dev
	</source>		</source>

Pio2pio: /* Sed - Stream Editor */

2022-04-08T16:03:54Z

Sed - Stream Editor

@@ Line 334: / Line 334: @@
 Reference:
 * [https://stackoverflow.com/questions/34942796/shell-cmd-date-without-new-line-in-the-end shell-cmd-date-without-new-line-in-the-end] Stackoverflow
 = Sed - Stream Editor =

Pio2pio: /* String manipulation | parameter substitution */

2022-01-25T20:06:17Z

String manipulation | parameter substitution

← Older revision		Revision as of 22:06, 25 January 2022
Line 785:		Line 785:
	<source lang="bash">		<source lang="bash">
	# Strip the longest match ## from the beginning(hashbang) of the string matching pattern(`* `). It matches any number of characters and a <space> .		# Strip the longest match ## from the beginning(hashbang) of the string matching pattern(`* `). It matches any number of characters and a <space> .
	host="box-1.~~company~~.cloud 22"; echo ${host##* } # -> 22		host="box-1.acme.cloud 22"; echo "${host##* }" # -> 22 # pattern `* `
	host="https://google.com" ; echo ${host##*/} # -> google.com		host="https://google.com" ; echo "${host##/}" # -> google.com # pattern `/`

	# Strip the longest match %% from end(percentage) of the string, matching pattern `<space>` and `*` anything (fileglob )		# Strip the longest match %% from end(percentage) of the string, matching pattern `<space>` and `*` anything (fileglob )
	host="box-1.~~company~~.cloud 22"; echo ${host%% *} # -> box-1.~~company~~.cloud		host="box-1.acme.cloud 22"; echo "${host%% }" # -> box-1.acme.cloud # pattern ` `
	~~HOSTNAME~~=api-uat-1; echo "${~~HOSTNAME~~%%-}" # -> api # ~~patern~~ `-`		host="api-uat-1" ; echo "${host%%-}" # -> api # pattern `-`

	# Strip the longest match (%%) from end of string (percentage), [0-9]* regex matching any digit		# Strip the longest match (%%) from end of string (percentage), [0-9]* regex matching any digit
	vpc=dev02; ${vpc%%[0-9]*}		vpc=dev02; echo "${vpc%%[0-9]}" # -> dev # pattern `[0-9]`

	# Strip end of string '.aws.company.'; file globing allowed or ". " is a regEx unsure		# Strip end of string '.aws.company.'; file globing allowed or ". " is a regEx unsure
	host="box-1.prod1.midw.prod20.aws.~~company~~.cloud"; echo ${host%.aws.~~company~~.*}		host="box-1.prod1.midw.prod20.aws.acme.cloud"; echo ${host%.aws.acme.*}
	</source>		</source>

Pio2pio: /* String manipulation | parameter substitution */

2022-01-25T19:59:54Z

String manipulation | parameter substitution

← Older revision		Revision as of 21:59, 25 January 2022
Line 784:		Line 784:
	=== String manipulation \| parameter substitution ===		=== String manipulation \| parameter substitution ===
	<source lang="bash">		<source lang="bash">
	# ~~strips out~~ the longest match (%%) from end of string (percentage), [0-9]* regex matching any digit		# Strip the longest match ## from the beginning(hashbang) of the string matching pattern(`* `). It matches any number of characters and a <space> .
			host="box-1.company.cloud 22"; echo ${host##* } # -> 22
			host="https://google.com" ; echo ${host##*/} # -> google.com

			# Strip the longest match %% from end(percentage) of the string, matching pattern `<space>` and `*` anything (fileglob )
			host="box-1.company.cloud 22"; echo ${host%% *} # -> box-1.company.cloud
			HOSTNAME=api-uat-1; echo "${HOSTNAME%%-}" # -> api # patern `-`

			# Strip the longest match (%%) from end of string (percentage), [0-9]* regex matching any digit
	vpc=dev02; ${vpc%%[0-9]*}		vpc=dev02; ${vpc%%[0-9]*}

	# Strip end of string '.aws.company.'; file globing allowed or ". " is a regEx unsure		# Strip end of string '.aws.company.'; file globing allowed or ". " is a regEx unsure
	host="box-1.prod1.midw.prod20.aws.company.cloud"; echo ${host%.aws.company.*}		host="box-1.prod1.midw.prod20.aws.company.cloud"; echo ${host%.aws.company.*}
			</source>

	~~# Strip string from the beginning of matching pattern, '*' matches any number of characters and <space>~~
	~~host="box-1.company.cloud 22"; echo ${host##* } # -> 22~~
	~~host="https://google.com" ; echo ${host##*/} # -> google.com~~

	~~# Strip from the back %% (longest match) of matching pattern <space> and '*' anything (fileglob )~~
	~~host="box-1.company.cloud 22"; echo ${host%% *} # -> box-1.company.cloud~~

	~~# Strip from the back %% (longest match) of matching pattern '-' and '*' anything (fileglob )~~
	~~echo $HOSTNAME # -> api-uat-1~~
	~~echo "${HOSTNAME%%-*}" # -> api~~
	~~</source>~~
	=== Default value and parameter substitution ===		=== Default value and parameter substitution ===
	<source lang="bash">		<source lang="bash">

Pio2pio: /* Expansions - string manipulation */

2022-01-25T19:47:05Z

Expansions - string manipulation

← Older revision		Revision as of 21:47, 25 January 2022
Line 780:		Line 780:
	== Expansions - string manipulation ==		== Expansions - string manipulation ==
	*[http://www.tldp.org/LDP/abs/html/parameter-substitution.html parameter-substitution] tldp.org/LDP		*[http://www.tldp.org/LDP/abs/html/parameter-substitution.html parameter-substitution] tldp.org/LDP
	*[https://unix.stackexchange.com/questions/122845/using-a-b-for-variable-assignment-in-scripts/122878 ~~using-~~a-b-for-variable-assignment-in-scripts] unix.stackexchange.com		*[https://unix.stackexchange.com/questions/122845/using-a-b-for-variable-assignment-in-scripts/122878 Using "${a:-b}" for variable assignment in scripts] unix.stackexchange.com

	=== String manipulation \| parameter substitution ===		=== String manipulation \| parameter substitution ===

Pio2pio: /* Expansions - string manipulation */

2022-01-25T19:46:26Z

Expansions - string manipulation

← Older revision		Revision as of 21:46, 25 January 2022
Line 779:		Line 779:
	</source>		</source>
	== Expansions - string manipulation ==		== Expansions - string manipulation ==
			*[http://www.tldp.org/LDP/abs/html/parameter-substitution.html parameter-substitution] tldp.org/LDP
			*[https://unix.stackexchange.com/questions/122845/using-a-b-for-variable-assignment-in-scripts/122878 using-a-b-for-variable-assignment-in-scripts] unix.stackexchange.com

	=== String manipulation \| parameter substitution ===		=== String manipulation \| parameter substitution ===
	<source lang="bash">		<source lang="bash">

Pio2pio: /* References */

2022-01-25T19:46:11Z

References

← Older revision		Revision as of 21:46, 25 January 2022
Line 798:		Line 798:
	echo "${HOSTNAME%%-*}" # -> api		echo "${HOSTNAME%%-*}" # -> api
	</source>		</source>
	~~==== References ====~~
	*[http://www.tldp.org/LDP/abs/html/parameter-substitution.html parameter-substitution] tldp.org/LDP
	*[https://unix.stackexchange.com/questions/122845/using-a-b-for-variable-assignment-in-scripts/122878 unix.stackexchange.com]

	=== Default value and parameter substitution ===		=== Default value and parameter substitution ===
	<source lang="bash">		<source lang="bash">

Pio2pio: /* Script path - execute a script not in current working directory */

2021-11-25T09:54:30Z

Script path - execute a script not in current working directory

← Older revision		Revision as of 11:54, 25 November 2021
Line 691:		Line 691:
	cd "$SCRIPT_PATH" \|\| exit 1		cd "$SCRIPT_PATH" \|\| exit 1

	Option 2 - from K8s repo tree		# Option 2 - from K8s repo tree
	SCRIPT_ROOT=$(dirname ${BASH_SOURCE})/..		SCRIPT_ROOT=$(dirname ${BASH_SOURCE})/..
	~~</source>~~

	~~<source lang=bash>~~
	~~command \|\| { echo "command failed"; exit 1; }~~

			# Option 3
	DIR="$(dirname $(realpath $0))" # this works also if you reference symlinks and will return hardfile path		DIR="$(dirname $(realpath $0))" # this works also if you reference symlinks and will return hardfile path

	# ~~Set~~ magic variables for current file & dir		# Option 4 - magic variables for current file & dir
	__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"		__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
	__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"		__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"

Pio2pio: /* Other examples */

2021-11-25T09:53:14Z

Other examples

← Older revision		Revision as of 11:53, 25 November 2021
Line 695:		Line 695:
	</source>		</source>

	~~=== Other examples ===~~
	<source lang=bash>		<source lang=bash>
	command \|\| { echo "command failed"; exit 1; }		command \|\| { echo "command failed"; exit 1; }