Chapter 4 LINUX Shells Table 4 1 Shell

Chapter 4 LINUX Shells

Table 4. 1 Shell Locations and Program Names

Figure 4. 1 Shell families and their relative functionalities

Table 4. 2 Shell Similarities and Disimilarities

Table 4. 2 Shell Similarities and Disimilarities (continued from previous slide)

Table 4. 3 Some Useful Shell Built-In Commands

Table 4. 4 Shell Environment Variables

Table 4. 5 Shell Startup Files for Bash and TC Shells

Shell Startup Files • Startup files set environment variables and set the initial behavior of the shell • Bash first runs the file /etc/profile • Additional startup files have names that start with “. ” which denotes a hidden file

Figure 4. 2 An illustration of the write command (continued on next slide)

Figure 4. 2 An illustration of the write command (continued from previous slide

Table 4. 6 Some Useful Aliases

Some Useful Commands Directory commands: pwd, mkdir, rmdir, ls File display commands: cat, more, less File printing: lpr Calendar display: cal Instant Messaging: write, talk (can be enabled or disabled using mesg) • Email notification: enabled or disabled using biff • Aliasing: create an alias name for long commands (alias, and unalias) • System statistics: uptime, ps • • •

Shell Metacharacters • Metacharacters are characters that have a special meaning to the shell • Metacharacters can be used as regular characters by preceding them with “”

Table 4. 7 Shell Metacharacters (continued on next slide)

Table 4. 7 Shell Metacharacters (continued from previous slide)