Shell – Parte 3

COMANDOS QUE TRATAM VARIAVEIS

echo

Exibe o conteudo de uma variavel.

SINTAXE:
echo variavel
EXEMPLO:
informix@isis:~> echo $HOME
/usr/informix
informix@isis:~> echo $PATH
/usr/informix/bin:/usr/informix/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin
informix@isis:~>

set

Lista as variaveis do ambiente shell.

SINTAXE:
set
EXEMPLO:
informix@isis:~> set
BASH=/bin/bash
BASH_VERSINFO=([0]="3" [1]="2" [2]="39" [3]="1" [4]="release" [5]="x86_64-suse-linux-gnu")
BASH_VERSION='3.2.39(1)-release'
COLORTERM=1
COLUMNS=134
CONSOLE_MAGIC='(K'
CPU=x86_64
CSHEDIT=emacs
DBCENTURY=C
DBDATE=dmy4/
DBMONEY=,
DIRSTACK=()
ENV=/etc/bash.bashrc
EUID=107
FROM_HEADER=
GROUPS=()
G_BROKEN_FILENAMES=1
G_FILENAME_ENCODING=@locale,UTF-8,ISO-8859-15,CP1252
HISTCONTROL=ignoreboth
HISTFILE=/usr/informix/.bash_history
HISTFILESIZE=1000
HISTSIZE=1000
HOME=/usr/informix
HOST=isis
HOSTFILE=
HOSTNAME=isis
HOSTTYPE=x86_64
IFS=$' \t\n'
INFODIR=/usr/local/info:/usr/share/info:/usr/info
INFOPATH=/usr/local/info:/usr/share/info:/usr/info
INFORMIXDIR=/usr/informix
INFORMIXSERVER=tst
INPUTRC=/usr/informix/.inputrc

export

Exporta uma variavel e seu valor aos processos filhos.

SINTAXE:
export variavel
COMENTARIO:
Variaveis são validas no processo onde elas são definidas (Variaveis local). As variaveis exportadas são chamadas de variaveis globais.
EXEMPLO:
informix@isis:~> INFORMIXDIR=/usr/informix
informix@isis:~> JAVA_HOME=/usr/java
informix@isis:~> export INFORMIXDIR JAVA_HOME
informix@isis:~>

env

Lista as variaveis que foram exportadas (variaveis globais).

SINTAXE:
env
EXEMPLO:
informix@isis:~> env
LESSKEY=/etc/lesskey.bin
NNTPSERVER=news
INFODIR=/usr/local/info:/usr/share/info:/usr/info
MANPATH=/usr/local/man:/usr/share/man
HOSTNAME=isis
XKEYSYMDB=/usr/share/X11/XKeysymDB
HOST=isis
SHELL=/bin/bash
TERM=xterm
PROFILEREAD=true
HISTSIZE=1000
INFORMIXDIR=/usr/informix
MORE=-sl
USER=informix
LD_LIBRARY_PATH=/usr/informix/lib:/usr/informix/lib/esql
XNLSPATH=/usr/X11R6/lib/X11/nls
ENV=/etc/bash.bashrc
DBMONEY=,
DBCENTURY=C
HOSTTYPE=x86_64
FROM_HEADER=
ONCONFIG=onconfig.tst
PAGER=less
DBDATE=dmy4/
CSHEDIT=emacs
XDG_CONFIG_DIRS=/etc/xdg
MINICOM=-c on
MAIL=/var/spool/mail/informix
PATH=/usr/informix/bin:/usr/informix/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/usr/lib/mit/bin:/usr/lib/mit/sbin
CPU=x86_64
INPUTRC=/usr/informix/.inputrc
PWD=/usr/informix